China email database free

Structured query language
Objectives
After having studied this unit, you’ll be able to:
Explain SQL and the various data types
Define the fundamental structures of SQL queries.
Learn how to make tables
Perform Null and aggregate values and functions
Sartaj Singh Lovely Professional University

38 AMAZING PROFESSIONALS UNIVERSITY
Database Management Systems/Managing Database
Notes Introduction

SQL refers to Structured Query Language (SQL). This is one of the commonly used commercial relational
database language. SQL has established its position as the leading relational-database language
languages. There are a variety of variations of SQL. The initial SQL. Version was developed by
IBM’s San Jose Research Laboratory (now the Almaden Research Centre). This language was
Originally referred to as Sequel initially, it was part of the System R Project in early 1970s. The Sequel
The language has changed since the beginning, and its title has been changed SQL (Structured SQL Query Language).
SQL makes use of a combination of relational algebra as well as relational calculus. While SQL language is
Also known as “Query language” and it has many more capabilities , besides querying data bases.
Inside this DBMS, SQL will be used to create tables, translate requests from users keep the information
Dictionary Maintain the catalog of the system maintain and update the tables, set up security and
Perform steps to backup and recover.
3.1 Structured Query Language (SQL)

SQL (pronounced “ess-que-el”) refers to Structured Query Language. SQL is employed to
It is a way to communicate with databases. Based on ANSI (American National Standard Institute) it is
the language used for relational database management systems. SQL statements are utilized to
accomplish tasks like updating the database’s data and retrieve information from databases. Common
SQL-based relational databases that make use of SQL include: Oracle, Sybase, Microsoft SQL Server,
Access, Ingres, etc. While the majority of databases use SQL however, many also possess their own
Additional extensions from proprietary developers that are generally only utilized by the system. However, they can be used on other systems.
common SQL commands like “Select”, “Insert”, “Update”, “Delete”, “Create”, and “Drop”
Databases can be used to do nearly everything one could want to accomplish using a database.
The SQL language is comprised of several components:

China email leads

1. The Data Definition Language (DDL) is the name given to it. SQL DDL provides commands for the definition of relations.
schemas, deleting relationships and changing schemas for relation.
2. Interactive data-manipulation languages (DML) is the SQL DML includes a query language
It is based on the relational algebra and tuple-based calculus. It also includes
instructions to add tuples in, delete tuples from, or modify tuples stored in databases.
3. View definition: SQL DOL includes commands for the definition of views.
4. Controlling transactions: SQL includes commands for setting the beginning and the end of
transactions.
5. The embedded SQL and dynamic SQL dynamic SQL define the way SQL statements will be executed.
It is possible to integrate general-purpose programming languages like C, C++, Java,
PUr, Cobol, Pascal Cobol, Pascal, PUr and Fortran.
6. Integrity In the SQL DDL includes commands for specifying integrity restrictions that are included in the
The data stored in the database must meet. Updates that don’t meet integrity restrictions are considered to be insecure.
disallowed.
7. Authorization authorization: The SQL DDL includes commands for defining access rights for relations
and views.

China email lists download

3.2 Data Definition
The definition of data in SQL is done through creating statements.

This statement is used to create tables,
index and view (i.e. it is a virtual table based upon tables that exist). For the creation of a table, you must use the create statement is used.
SUPER PROFESSIONAL UNIVERSITY 39
3. Unit: Structured Queries Language
Notes defines the table’s name as well as the names and data types for every column of the table. It’s
Format is:
Create tables (relation> ( )
in which an attribute listing is defined in the form of:
:: = ( )[not null]
The types of data that are supported through SQL will depend upon the specific implementation. However the
The following types of data are typically comprised: decimal, integer and real (i.e. floating points),
and characters and character strings and lengths that vary. There are a variety of values are available for character strings.
The integer data type is generally accepted, such as smallint and integer. The decimal value
declarations require the specification of how many decimal numbers for the value , as well as
(optionally) (optionally) of digits that lie to the right to the right. (optionally), the number of fractional
decimal digits are assumed to be zero when only the number of decimal digits is stated.
:: = | | | |
Furthermore, some implementations support additional data types , including bit strings or graphics
strings that are logical, data and time. Some DBMSs allow the concept of dates. One possibility is that they support the concept of date.
The date’s implementation can be as simple as eight decimal digits that are not signed, which represent the data in the
yyyymmdd format. The year is represented by yyyyyyyyyyyyy while mm represents the month and dd signifies
the day. Two dates are compared to find the one with more and consequently occurs later. The
System ensures that only valid date values are used (19860536 to insert the year is illegal)
and functions are available and functions are provided to carry out operations, such as and functions are provided to perform operations such as adding a number of days to a date
find a different date, or subtract a date by the present date to determine the amount of
months, days or years. Date constants are available in the format described above or in an
character string that is in one of the following formats: mm/dd/yy the format mm/dd/yyyyyyyyy;
dd-mm-yyyy. The unit we use is dd-mm-yyyyy. define the date constant in eight decimal numbers that are unsigned in the
format yyyymmdd.

3.3 Data Types
In its broadest sense the term “data type” describes a set of values, as well as the permitted operations for those values.
values. Most programming languages explicitly contain the concept of data types, but
different languages may use different terminology. The majority of programming languages allow
The programmer is able can define additional data types typically by combining several elements of
different types and delineating the proper operations for the new type of data.
For instance, a programmer could create a new type of data called “Person” that defines
The data that can be could be interpreted as Person could include a name as well as a day of birth.

China consumer email database

Common data types could include:
1. Integers,
2. Numbers with floating-points (decimals) as well as
3. Alphanumeric strings.
Example in Java, the Java programming language”int” type in Java programming language “int” type is the 32-bit set.

integers with values ranging between -2,147,483,648 and 2,147,483,647 in addition to the operations that are able to
are performed on integers for example, subtraction, addition as well as multiplication. Colors, on the contrary
Hand, are represented with three bytes, which represent the sums each of green, red blue, and red, as well as one
40 LOVELY PROFESSIONALS UNIVERSITY
Database System Management/Managing Database
Notes string that represents the color’s color name; allowed operations include subtraction and addition,
But not multiplication.

China email lists

A data type may be thought of as a restriction placed on how data is interpreted within the context of a particular type
system that describes the structure, representation and interpretation of objects or values stored in
Computer memory. The type system utilizes the information about data types to determine the validity the compatibility of computer programs
who can access or alter the that access or manipulate the.
Below are the top commonly used data types:
char(size) fixed-length character string. Size is defined in parenthesis. Maximum size is 255 bytes.
Varchar(size) Character string with variable length. The maximum size is defined in parenthesis.
number(size) Value of a number with a maximum the number of column digits in parenthesis.
Date Date Value
number(size,d) number value that has the maximum number of digits in “size” in total, as well as a
the maximum quantity of “d” numbers to the left of the decimal.

3.4 Schema Definition
It is the general structure that is known as a database schema. The schema of a database is typically graphical.
The database is presented in a comprehensive manner. Tables are linked to keys from other sources and key colums.
If you are accessing data from multiple tables, the schema of the database will be required to identify
joining data elements , and when the case is complex, finding appropriate intermediate tables. Some database
The products utilize the schema to join tables automatically.
The database system is comprised of several schemas in accordance with the degree of abstraction. The physical schema
The schema describes the database design at the physical level. The schema logically describes the design of the database
at a logical at a logical level. The database could also have the sub-schemas (view level) that describe various views
of databases.
3.5 The Basic structure of SQL Queries
The most common format for an SQL queries is the following:
Select [DISTINCT] select-list
FROM the from-list

 Email marketing database China

1. Select Clause Select is a command taken from DML language that can be used to select a specific
columns of tables. Each SQL query starts with the SELECT keyword.

It is followed by
The list of columns that form the relationship.
2. From: This section specifies the table names that data should be pulled.
FROM is followed by list of range values that is unique to a table in the event that it
Names are repeated more than one time.
3. The keyword Where: WHERE is used to indicate the conditions. All the tuples that meet the
The conditions are chosen.
4. Distinct: The purpose of the keyword Distinct is intended to avoid duplicate rows in the event that this keyword is used.
It is utilized to ensure that all is used and all the tuples in the table are distinct. It is the only way to ensure that there is no duplicate data. The purpose of this
The keyword is not mandatory.
5. Select-List: List of all column names the user would like to use in the new relationship.
AWESOME PROFESSIONAL UNIVERSITY 41
3. Unit: Structured Queries Language
Notes6. Qualification: It’s an expression that is boolean and represents the condition that has the logical
connectives as well as compare operators.
These tables will be utilized during the entire unit
Employee

China email data

Etoys in Squeak built upon this player-and-viewer model, merging parts of the “observer.”

The Idea with Smalltalk’s message-passing model. It also drew substantially from a tradition of

iconic programming research at Apple and elsewhere.

Iconic programming—

composing program-like structures by manipulating graphical elements on screen—dates

back to Ivan Sutherland’s Sketchpad and the RAND Corporation’s early pen-based GRAIL

system and has been sought after ever since. Kay mentions having iconic programming in

mind in the first Dynabook concepts (Kay 1996 a, p. 552). David Smith’s PYGMALION

system (“an executable electronic blackboard”), which dates from the mid-1970s at Xerox, is

an early and celebrated iconic programming environment (Smith, 1993). Smith and Allen

Cypher later worked on an iconic programming system called Cocoa while at Apple

Computer (Cocoa was commercialized in 1999 as Stage case Creator). 

And during his brief

stay at Apple in the mid-1980s, Dan Ingalls (along with Scott Wallace and others who would

later create Squeak) created a Smalltalk-based iconic programming environment called

Fabrik. An Apple “Advanced Technology Group Research Note” (Chesley et al., 1994) anti-

titled End-User Programming: Discussion of Fifteen Ideas illustrates the kind of thinking that

was active in the mid-1990s: throughout, direct manipulation and visual concreteness are

vital virtues.

Kay’s touchstone was his reading of Jerome Bruner’s model of three distinctive modes

of thinking: concrete, iconic, and symbolic (Bruner 1966, p. 11ff; Kay 1990, p. 195ff)—that

these are not developmental stages we pass through so much as styles of thinking that we

use in different combinations in different contexts. The way forward, according to this

the thinking was not simply to replace the symbolic with the iconic—that is, to replace

program code with iconic representations—but to recognize and nurture the interplay

Chapter 7: Squeak’s Small but Mighty Roar 237

among all three. 

A vital reminder of this was the straightforward success of Bill Atkinson’s

HyperCard, which, while being much simpler (and more restrictive) conceptually than any

of the Smalltalks, facilitated simple scripting by attaching messages to buttons or text fields

on the screen. A user could use graphics tools to create an onscreen object, thereby making

something concrete to work and think with—and then attach some scripting or message-

sending to it. Kay’s team took up this simple insight for Etoys (Ted Kaehler,

personal communication, October 2004): allowing direct manipulation of objects (that is,

onscreen with the mouse) to lead to scaffolded scripts, one line at a time, and then to further

generalized programming at the point when it seems easier to move to the more abstract

form.

What Etoys provides is a visual programming environment that is a blend of the direct-

manipulation of iconic style and the textual/symbolic approach. Any graphical object (Etoys

encourages one to begin with a graphic object) can be scripted by opening a “Viewer” very

much like the one sketched out in the 1979 World Book chapter; this presents several

the object’s attributes (position, heading, etc.) to be shown in a list of direct-manipulation

windows.

Buy China email database

The absence of a distinct wording led to the vow (Henry 22000) that is then repeated
twice. This is known as a multipleset of rows. It is an array of unrelated rows.

elements that could comprise multiple copies of the identical element, but not the total amount of
duplicates of the element are essential. For instance, the set (1,2,1,1,) and (2,1,1,1) are the same
multiset. Each has three copies of the ‘1″ and only one duplicate of ‘2’. However, this multiset (1,2,2,1)
is different. The number of copies of every element is an important criterion to distinguish
between two sets.
The result is not ad-hoc, without the word “DISTINCT”
The result is obtained with the help of DISTINCT Keyword
AWESOME PROFESSIONAL UNIVERSITY 43
3. Unit: Structured Queries Language
NotesRules to Follow for Query Evaluation
Consider a simple query, Query

(b): Search for (b) Search for who are the employees working in the accounting department.
Solution:
Select E.ename
From Employee E Department D,
Where E.eid equals D.Dept_managerid AND
D.Dname = ‘Accounting’.
To resolve this problem, follow these steps as illustrated
1. Calculate the cross-product of the tables whose names appear in the from-list.
Eid Ename D.No. Esal Age Phone Dept.
Manage
rid

3. The columns’ names that aren’t listed in the select-list are removed.
4. Take out the rows that have been duplicated when the specific keyword isn’t utilized.
Now let’s take these steps in the context of table E for employees.

China companies email database

Squeak’s Small but Mighty Roar 238

At the most immediate, the values of the various

parameters can be changed, either by typing or by

choosing possible values from a menu.

Some of the parameters are animation oriented: for each “tick.”

of a system clock, any parameters concerned with

changes—position, heading, etc.—will update by

the specified amount. The result is that simply by

clicking and typing in the Viewer window, the

object can be made to change and move immedi-

ately. The second step is dragging a “script” window

from the Viewer. Once this has been done,

“tile-based” programming is available. Parameters

from the Viewer can be drag-and-dropped into the

script; here is where the tradition of iconic

programming intersects with Etoys. With a script

constructed, running the “ticker” system clock

causes the script to be executed (looping is the

usual behaviour). 

The script can be modified as it is

running by dragging new items from the Viewer or removing them, or by changing the

values of object parameters. Conditional “tests” can be dragged in as well, again, using the

Viewer parameters as components. So a good deal of programming functionality can be

accomplished simply by dragging and dropping parameters and script components and by

directly manipulating the parameters in real-time (this also provides a real-time update of

the various parameters). With just what I have described, most Lego-style turtle genomes-

try can be accomplished via direct manipulation: no “code” needs to be written.

However, since Etoys is merely an interface to Squeak Smalltalk, there is a traditional

Smalltalk code representation lurks in each Etoys object as well; it is possible to toggle

between the draggable “script” version and a more traditional code editor window.

The Morphic User Interface Framework

The technology that makes dragging and

the dropping of script components works in the

Etoys environment is due to Squeak’s

primary GUI toolkit, called Morphic.

Morphic was initially developed as part of

a blue-sky research environment called Self

at Sun Microsystems in the late 1980s and

the early 1990s. Self was designed to be a

completely direct-manipulation program-

ming environment; its goal was to leapfrog

Smalltalk in terms of conceptual simplicity

(“Self is like Smalltalk, only more so,” wrote

its original designer, David Ungar).

John Maloney, who had worked on the

Self-project while at Sun joined Alan Kay’s

the team at Apple in 1995 and brought the

Morphic interface with him; he re-

implemented it in Squeak, and 1997

Morphic became the foundation of

Squeak’s—and Etoys’—user interface.

Morphic has been a double-edged sword

for Squeak. While it is arguably one of the

most malleable graphics environments ever

developed, and while it supports the ideal in

Squeak that everything in the

the system should be manipulable; this may

also, it can be a drawback for newcomers to the

system.

 Indeed, much of the criticism of

A squeak from the computer science

community is centred around the

bewildering collection of layers and

components which confront the user

looking at Squeak (see WikiWikiWeb:

MorphicInterface).

Buy China email database

To create a table, you must enter the keywords create table , followed by the table’s name then
An open parenthesis is followed by the column’s first name, then the type of data for that
column and then any other constraints that may be optional that are followed by an end parenthesis.

It is important to make sure you use an open parenthesis prior to the table’s beginning and also a closing
parenthesis at the end of the definition of the last column.
Be sure to separate every column’s definition with a punctuation mark. Each of the SQL statements must end with a
with the help of “;”.

The table’s name and column’s name should begin with a letter. They may be followed by numbers, alphabets, numbers or
underscores do not exceed the total length of 30 characters. Don’t utilize any SQL reserved
Keywords are used as names for tables as well as column titles (such for example “select”, “create”, “insert”, etc. ).
Data types determine what type of data is for that specific column. If a column is called
“Last_Name” is intended designed to store names, then that specific column must be the designation “varchar”
(variable-length characters) (variable-length character).
3.7 DML Operations
Various DML (Data Manipulation Language) commands
1. Select is used to select various columns
2. INSTALL to insert the data in tables
3. UPDATE to update the information
4. DELETE to erase the data.
3.7.1 The SELECT Command
The command SELECT is made up of strings and expressions. In the form of the SQL query
The select-list includes:
1. Expressions and
2. Name of the column
Structured query language

Objectives
After completing this unit, you’ll be able to:
Define SQL and the various data types
Define the fundamental structures of SQL queries.
Know how to design tables
Perform Null and aggregate values and functions
Sartaj Singh Lovely Professional University
38 AMAZING PROFESSIONALS UNIVERSITY
Database System Management/Managing Database

Notes Introduction
SQL is a shorthand for Structured Query Language (SQL). This is one of the popular commercial relational
database language. SQL has proven its position as the leading relational-database language
languages. There are many variations of SQL. The initial SQL. Version was developed by
IBM’s San Jose Research Laboratory (now the Almaden Research Centre). This language was
Originally referred to as Sequel originally referred to as Sequel, was a part of the System R Project in early 1970s. The Sequel
Language has developed since it was first introduced, and the title has been changed SQL (Structured SQL Query Language).
SQL makes use of a combination of relational algebra and calculus. However, the SQL language is
Also known as “Query language” It has many other features, besides using a data-base to query.
In this DBMS, SQL will be utilized to build tables, translate requests from users and maintain the data
Dictionary keep the system catalog update and maintain the tables, set up security and
Perform the backup and recovery procedure.

China email id list

SQL (pronounced “ess-que-el”) is a shorthand for Structured Query Language. SQL is employed to
connect to databases.

As per ANSI (American National Standard Institute) it is
the language used for relational databases management systems. SQL statements can be used to
Perform tasks like updating databases and retrieve information from databases. A few common
Relational databases management systems that make use of SQL include: Oracle, Sybase, Microsoft SQL Server,
Access, Ingres, etc. Although the majority of database systems utilize SQL but a majority of them also come with their own
Additional extensions from proprietary developers which are typically only available for their own systems. However, they can be used on other systems.

China email lists

Standard SQL commands like “Select”, “Insert”, “Update”, “Delete”, “Create”, and “Drop”
It can be used for nearly everything one could want to accomplish using a database.
The SQL language comes in several parts:
1. DDL stands for Data Definition Language (DDL) The SQL DDL provides commands for creating a definition of a relationships.
schemas, deleting relationships and changing schemas for relation.
2. Interactive data-manipulation languages (DML) is the SQL DML includes a query language
Based on both the relational algebra as well as the tuple calculus. It also includes
instructions to add tuples in, delete the tuples, and alter tuples stored in databases.
3. View definition: SQL DOL includes commands for creating views.
4. Controlling transactions: SQL includes commands for specifying the starting and ending of
transactions.
5. embedded SQL as well as dynamic SQL dynamic SQL define the way SQL statements are interpreted.
It is possible to integrate general-purpose programming languages like C, C++, Java,
PUr, Cobol, Pascal Cobol, Pascal, PUr and Fortran.
6. Integrity In the SQL DDL includes commands for specifying integrity-related constraints.
The database’s data must be able to meet. Updates that don’t meet integrity restrictions are considered to be insecure.
disallowed.
7. Authorization authorization: The SQL DDL includes commands for giving access rights to relational entities.
and views.
3.2 Data Definition
The data definition in SQL is done through the statement create. This statement is used to create tables,
index also known as view (i.e. an online table that is based on tables already in use). For the creation of a table, you must use the create statement is used.
AWESOME PROFESSIONAL UNIVERSITY 39
Third Unit: Structured Queries Language
Notes defines the table’s name and the names as well as types of data for each column in the table. Its
Format is:
Create tables (relation> ( )
in which attributes are defined with the following format:

Chinese email database

The types of data that are supported in SQL will depend upon the specific implementation. However SQL supports a variety of data types, including
The following types of data are typically comprised: decimal, integer and real (i.e. floating-point values),
and characters and character strings, both of fixed size and lengths that vary.

A variety of values are available for character strings.
Integer data types are typically accepted, including smallint and integer. The decimal value
declaration must specify an exact number of decimal digits in the amount and
(optionally) (optionally) of digits that lie to the right to the right. (optionally), the number of fractional
decimal digits are assumed to be zero if the number of decimal digits is stated.
:: = | | | |

China email lists

Additionally, certain implementations support additional data types , including bit strings and graphic
strings that are logical, data and time. Certain DBMSs are able to support the concept of dates. One possibility is that they support the concept of date.
The date’s implementation can be as simple as eight unsigned decimal numbers representing the information in the
yyyymmdd format. The year is represented by yyyyy while mm represents the month, while dd refers to
the day. Two dates are compared to find the one with more and consequently occurs later. The
The system makes sure that only date values that are legal are used (19860536 to insert the year is illegal)
and functions are available and functions are provided to carry out operations, such as and functions are provided to perform operations such as adding a number of days to a specific date
Find a new date or subtracting a day by the present date to determine the amount of
months, days or years. Date constants are available in the format described above or in an
string of characters with one of the formats below: mm/dd/yy Dd-mm-yyyyyy
dd-mm-yyyy. The unit we use is dd-mm-yyyyyy. define the date constant in eight decimal numbers that are unsigned in the
format yyyymmdd.

Squeak’s Small but Mighty Roar 239

Figure 7.4: Etoys tile representation and equivalent Smalltalk code

The effect is that Kay’s Bruner-esque “Doing with Images makes Symbols” is embodied

most directly in the Etoys interface: concrete, direct manipulation is the most immediate

kind of interaction made possible here; iconic tiles that can be used as stand-ins for black-

boxed functionality (such as the Logo-derived “move forward five steps”, or even, at a higher

level of organization, an entire script represented as an icon or tile), and the symbolic level is

available as well. The idea is that kids can encounter and explore the Etoy environment in

any (or any combination) of these styles.

Squeak vs Squeakland

Is Etoys what Squeak is all about? Yes and no; it is undoubtedly the central focus of Squeak-

land.org, the website and community established by Alan Kay’s nonprofit Viewpoints

Research Institute in Glendale, CA. Squeakland is the public face of Squeak in educational

contexts, and Etoys is what it is all about. As we shall see, Squeak has other faces, but

this one forms the core of the present discussion.

The Squeakland.org website offers about two dozen Etoy projects—these are downloaded-

able Squeak files can be accessed either via the Squeak web browser plugin or from a

complete Squeak installation. A “project” is an encapsulated multimedia artefact, typically consisting-

Chapter 7: Squeak’s Small but Mighty Roar 240

ing an Etoys simulation or tutorial (often as an “active essay”—that is, explanatory text

accompanied by several active Etoy components). These downloadable projects are

organized into rough curricular divisions: elementary school, middle school, and high school.

Some have been created by Viewpoints staff, but others are showcased works by children or

teachers.

B. J. Allen-Conn, a teacher at the LA Open School and Viewpoints executive director

Kim Rose has published a book of Etoys exercises (Allen-Conn & Rose, 2003) which

perhaps serves as the main text of the Squeak educational community. The book walks

through—tutorial-style—a series of Etoys exercises that deal in a roundabout fashion with

the concept of acceleration. The book begins with the usual Etoy starting point: 3 painting a

small graphic of a car. The car object is then made to move around the screen by adjusting

the parameters in the Viewer. Next, we are instructed to paint a steering wheel and param-

meters for the steering wheel are connected to those of the car so that when we rotate the

steering wheel object, the car turns left and right. This basic Etoy can be built in a couple of

minutes and is presented as an introductory Etoys exercise.

The “Montessori game” here is for the children to get most of their pay-off

playing in the hand-eye arena while gradually and subliminally gaining fluency

and appreciation of the power of symbols. (Allen-Conn & Rose 2003, p. 7)

3. The Etoys “car” exercise is featured as well in several of Alan Kay’s recent lectures and talks; it serves as the basic Etoys demo.

Chapter 7: Squeak’s Small but Mighty Roar 241

Figure 7.5: The hallmark “drive a car” Etoy, with the dynamic interaction between two objects,

represented by the two square tabs in the upper right; the Viewer panel for the

The car tab is open and visible here. Tiles such as “Wheel’s heading” can be simply

dragged and dropped as building blocks into a script (Allen-Conn & Rose, 2003).

From this direct-manipulation exercise, we are invited to begin scripting the car to behave

semi-autonomously, following an arbitrary track, and speeding up and slowing down. 

Then, two cars can be raced on the screen, and the concept of acceleration is introduced by distin-

gushing between speed (distance travelled per ‘tick’) and change in speed (one parameter

affecting another parameter). With a model for visualizing acceleration established, Allen-

Conn & Rose then turn to a discussion of gravity; we are invited to go outside and drop

different kinds of weights from a height, as with Galileo’s classic experiment. Squeak is re-

introduced as a multimedia tool at this point to examine frames of digital video shot of the

dropping weights. By measuring the distance travelled by the falling weights from frame to

frame, a concrete visualization (an “inscription,” in Latour’s terminology) of acceleration is

re-created; now, the earlier simulation model of acceleration can be adapted to a simulation

of gravity’s pull on falling objects (pp. 69–71).

China email lists

In its broad sense the term “data type” describes a set of values and the permitted operations for those values.
values. Nearly all programming languages incorporate the notion of data types, but
different languages may use different terminology. Many programming languages also permit
The programmer is able can define additional data types generally by combining different elements of
different types and delineating the proper operations for the new type of data.
For instance, a programmer could create a new type of data known as “Person” that defines
the data that is can be read as Person could include a name as well as a day of birth.

Buy China database online

Common types of data may include:
1. Integers,
2. Numbers with floating-points (decimals) as well as
3. Alphanumeric strings.
Example in Java, the Java programming language”int” type in Java programming language “int” type is the 32-bit array.
integers that range between -2,147,483,648 and 2,147,483,647 in addition to the operations that could
are performed on integers like subtraction, addition and multiplication. Colors, on the contrary
On the other hand, they are represented by three bytes, which represent the sums each of green, red and blue. one

40 LOVELY PROFESSIONALS UNIVERSITY
Database Management Systems/Managing Database
Notes string that represents the color’s name. Operation that is allowed include subtraction and addition.
However, it is not multiplication.
A data type may also be considered as a limitation placed on how data is interpreted within the form of a type
system that describes the representation, interpretation, and structure of objects or values stored in
Computer memory. The type system utilizes details about the type of data to verify the authenticity the compatibility of computer programs
who can access or alter the that manipulate or access the.
Below are the top commonly used data types:

China email lists

char(size) Character string with fixed length. Size is defined in parenthesis. Max . 255 bytes.
Varchar(size) String of characters with variable length. Maximum size is stated in parenthesis.
number(size) Value of a number with a maximum number column digits in parenthesis.
Date Date Value
number(size,d) Value of a number with the highest number of digits “size” in total, as well as a
Maximum amount of “d” numbers to the left of the decimal.
3.4 Schema Definition
The overall structure that is known as a database schema. A database schema is usually graphically designed.
A visual representation of the entire database. Tables are linked with Key colums and external key keys.
If you are accessing data from multiple tables, the schema of the database will be required to identify
connecting data elements and in more complex situations, to locate the appropriate intermediate tables. Some database
The products utilize the schema to join tables automatically.
The database system is comprised of several schemas in accordance with the degree of abstraction. The physical schema
The schema describes the database design at the physical level. The physical schema defines the database’s design
at the level of logical. The database could also have schemas that are subordinate (view level) which describe different views
of databases

China email database providers

3.5 The Basic Architecture of SQL Queries
The format for any SQL queries is the following:
Select [DISTINCT] select-list
FROM FROM-LIST
WHERE qualification

1. Select Clause The command SELECT comes that comes from the DML language that is used to select certain
columns of tables. The columns of the tables. SQL query begins with the SELECT keyword. It is followed by
the column list which form the resultant relationship.
2. From: This clause identifies the table names that data should be pulled.
From is followed by a number of range values, which is unique to a table when it is
Names are repeated more than one time.
3. The keyword Where: WHERE is used to define the condition. The tuples that satisfy the
the conditions that are selected.
4. Distinct: The purpose of this wording is used to avoid repetition of rows when using this keyword.
It is utilized to ensure that all is used and all the tuples in the table are is unique. It is clear that there is no duplicate data. The purpose of this
The keyword is not mandatory.
5. Select-List: A list of all column names that users want in the new relationship.
SUPER PROFESSIONAL UNIVERSITY 41
3. Unit: Structured Queries Language
Notes6. Qualification: It’s an expression in boolean form that represents the condition that has the logical
connectives as well as compare operators.
These tables will be utilized during the entire unit
Employee

China address list

Example: Consider a simple query,
Question (a) Choose the names and the salaries of employees whose pay exceeds 20000.

Solution:
SELECT DISTINCT E.ename, E.esal
From Employee E
WHERE E.esal > 20000.
42 VERY PROFESSIONAL UNIVERSITY
Database Management Systems / Managing Database
Notes The outcome the result of this SQL statement is the relationship.
It is interesting to consider that this is similar to using selection and projection techniques in
relational algebra.

In Allen-Conn & Rose’s treatment, Etoys seems aimed at teachers and schools; mostly

upper elementary and middle school. Kim Rose (personal communication, 2004) reports

Chapter 7: Squeak’s Small but Mighty Roar 242

that she works with a small (30-odd) but growing number of schools on a regular basis, help-

ing to support their use of Etoys; this represents a good proportion of the traffic on the

squeak and e-mail list.

But interestingly, when Etoys was first developed, schools were not the target; instead,

individual children (and parents) surfing the Internet were. Alan Kay explained it this way:

I should say a little about the history of Etoys. They were initially not aimed at

classrooms but as 10–20 minute projects supplied on the web for parents and

their children to do together. I stripped out as many features as I could and

tried to come up with a system that could do “100 examples” pretty straightfor-

wardly. The documentation that was intended here was to have been to teach

parents how to do the examples so they and their kids could have a good expe-

licence. For several reasons, this plan did not work out at Disney. But BJ [Allen-

Conn] saw it and wanted to try Etoys in her 5th-grade classroom. I was initially

against the idea because I thought that Etoys were not complete enough for

that venue. But she and Kim Rose decided to do it anyway. Six weeks later, they

started to show me some excellent results, and I realized that it would be

worth doing a three-year experiment to see how well the Etoys—even with some of

their lacks—would work out with ten and 11-year-olds. (Kay 2003 b)

Squeak in School

Squeak was not initially aimed at schools; indeed, homeschooling is a theme lurking just

under the surface of the Squeak philosophy. 4 Introducing Squeak to educators was not Orig-

finally a priority. Even the Etoys user interface, which represents a significant advance in

terms of kids having some leverage in a full-featured programming environment, was

thought of in its early years as something that curious children would find on the Internet

and become interested in. However, once BJ Allen-Conn picked up Squeak for use at the LA

Open School, Squeak became a school-based technology. And, one must admit, if one’s goal

is to reach children, schools are at least a good place to find them (Kim Rose, personal

communication, Oct 2004).

4. The Squeakland website lists “unschooling” advocate John Holt as one of its “Deep Influences on Thinking and Learning.”

(along with Bruner, Piaget, Montessori, and others).

Chapter 7: Squeak’s Small but Mighty Roar 243

Squeak’s open-source license is somewhat telling. By making Squeak an open, non-

the commercial entity, Kay and team, abandoned much of the traditional world of vendor-

driven educational technology. Squeak was aimed at children first, and then perhaps teach-

ers. In contrast, ‘successful’ educational technology projects seem to be aimed at

administrators and technology coordinators first. As such, Squeak has been spreading via

word-of-mouth rather than via a marketing campaign as such (Kim Rose, personal commu-

nication, Oct 2004). 

It is, however, tough to say anything definitive about the

extent of Squeak’s use by individual learners, parents, or even teachers; in the same way, it is

difficult to say how many workstations running Linux there are in the world. What we can

talk about with some certainty is what particular teachers have been doing with Squeak.

After the Vivarium Project ended at Apple Computer (around 1993), BJ Allen-Conn

maintained close contact with Alan Kay and Kim Rose, and continued to be part of their

circle for many years. Every summer for many years, Alan Kay has hosted a “Learning Lab.”

retreat at the Apple Hill Centre for Chamber Music in rural New Hampshire (the attendee

lists read like a who’s who in educational technology 5

). 

 China database for sale

ename, esal esal 20000( (Employee))
Therefore that the SQL query is like an expression that includes projection, selection and cross
product in relational algebra.

Notes Table is not a complete list of all the tuples with a salary that exceeds 20,000. The tuple
With the name “Henry” is displayed twice however it is only displayed with the name “Henry” is displayed only. It is because of the usage of
Keyword DISTINCT. If the keyword isn’t employed, then another tuple is required to be added to
table i.e. when we write,

The absence of a distinct wording led to an oath (Henry 22000) that is then repeated
twice. This is known as a multipleset of rows. It is an unsorted set of rows.
elements that may comprise several copies of the one element, however the total amount of
duplicates of the element are crucial. For instance, the sets (1,2,1,1,) and (2,1,1,1) are identical.
multiset. Each contains three copies of the ‘1″ and only one copy of the number ‘2’. However, this multiset (1,2,2,1)
is different. The number of copies of every element is a crucial criterion to determine the difference
between two sets.
The result is not a result without using the “DISTINCT” Keyword
The result is obtained with the help of DISTINCT Keyword
AWESOME PROFESSIONAL UNIVERSITY 43
Third Unit: Structured Queries Language
NotesRules to Follow when evaluating queries

 Buy China database for marketing

2. In the rows you get of the cross-product, eliminate those rows that don’t meet the criteria.
the qualification requirement.

3. The columns’ names that aren’t listed in the select-list are removed.
4. Take out the rows that have occurred twice, even though the keyword distinct is not employed.
Let us now apply these steps to an example of table E for employees.
Eid Ename DNo Esal Age Phone

This means it is likely that John as well as Harry represent the workers whose department’s name is “Accounts”.
Task in DBMS where you can make use of the WHERE clause.
3.6 Create Tables
The statement create table can be used to create the table. This is the format for an easy create
Table statement:

To create a table, you must enter the keywords create table , followed by the table’s name, then
An open parenthesis is followed by the column’s first name, then the data type that is associated with that column.
column and then any other constraints that may be optional that are followed by the closing parenthesis. It’s
Important to ensure that you ensure that you have an open paraphrase before the table’s beginning, and then a closing
Parenthesis following the conclusion of the column definition that was the last.
Make sure that you separate every column’s definition by a colon. Each of the SQL statements must end with a
with an “;”.
The table’s and column’s names must begin with a letter. Column names could be followed by numerals, letters or
underscores do not exceed the total length of 30 characters. Don’t utilize any SQL reserved
Keywords are used as names for tables and column name (such for example “select”, “create”, “insert”, etc. ).
Data types determine the kind of data that is for that specific column. If a column is called
“Last_Name” is intended designed to store names, then that specific column must have a “varchar”
(variable-length characters) Data type.

China email lists

At the 1997 retreat, Allen-Conn saw

an early version of Squeak. At the time, her technology curriculum at the LA Open School

relied on an amazingly widely varied suite of tools: Logo; Apple’s Cocoa (later Stage cast

Creator, a graphical “programming by demonstration” environment); AgentSheets and

HyperGami (simulation software and the 3D-modelling environment from the University of

Colorado); and Amy Bruckman’s MOOSE Crossing (a constructionist MOO environment

from the MIT Media Lab)—all these simultaneously. 6 But after seeing Squeak at Apple Hill,

she told Kay she wanted it for her classroom. 

Despite Kay’s initial reservations about using

Squeak in a classroom setting, Kay and Rose and colleagues set about getting a version

ready.

China email id

Allen-Conn began to replace the various software tools she was using, one by one,

with Squeak. The factor that made the difference for her, she says, was the amount of time

5. For more info about Kay’s Apple Hill retreat, see http://minnow.cc.gatech.edu/learninglab/17

6. BJ Allen-Conn’s ongoing connection to cutting-edge educational technology research is probably unparalleled among class-

room teachers.

Chapter 7: Squeak’s Small but Mighty Roar 244

the children spend problem-solving, compared with wrestling with the software (Allen-

Conn, personal communication, Nov 2004).

Since that time, Allen-Conn has represented the vanguard of educators using Squeak as

a curriculum tool, and one of the primary developers of the Squeak/Etoy-based curriculum

resources (such as the book she and Kim Rose published in 2003). Similarly, the LA Open

School has remained Kay’s educational testbed, although not at the scale it enjoyed while

Apple was funding whole-school, integrated curriculum research in the 1980s. Other nota-

ble users of Squeak in school settings include two schools in Toronto, where the school district

trustee Sheine Makovsky is a vocal advocate (Don Mills Middle School and Don Mills

Collegiate)

Beyond North America, it would appear that Squeak has more of a foothold. As the old

saying goes, Squeak is “big in Japan.” In fact, at a 2003 conference in Kyoto, “over 300 teach-

ers, students, researchers and developers gathered … to spend a day dedicated to talks and

sharing about Squeak, curriculum development, best practices and new Squeak media.”

These numbers must be compared to the 2004 and 2005 Squeakfest conferences, held in

Chicago, and which attracted 80 and 60 people respectively. 7 There is also Squeak activity in

Korea and Brazil.

China database email extractor

The most significant numbers may be in Europe; a substantial community of devel-

opers are found in Germany.

 In Spain, the regional government of Extremadura has

undertaken a very large-scale project to install open-source software in schools. Over

Sixty thousand computers are running Squeak on Linux there, though information about the actual use

of Squeak in classrooms is harder to come by. 8

Despite Squeak’s geographical distribution, though, the number of schools and teaching-

ers actually using Squeak is, frankly, small. There seems to be more ‘interest’ in Squeak as an

educational environment than there is actual practice. The squeak and mailing list, which is

specifically for educational topics, has very little traffic: 400+ subscribers but only a handful

of postings per week. By comparison, the squeak-dev list, which serves the programmer

Chapter 7: Squeak’s Small but Mighty Roar 245

the community has 1358 subscriptions as of the fall of 2005 and commonly runs to 20–30

messages per day.

Why isn’t Squeak a bigger deal, given its heritage, its flexibility, its goals, and its cost? The

reasons are not surprising, but they are worth outlining in some detail:

• Technology support in schools: The LA Open School is far from typical in its

commitment to technology for reasons both ideological and financial. BJ Allen-

Conn is quite sceptical of the idea that Squeak could spread significantly via ‘viral

marketing’ in a self-sustaining way. “Teachers need support,” she insists, in the

form of books and guides and one-on-one support; somebody has to teach the

teachers and make it possible—if not easy—for a teacher to actually pick up and

use something like Squeak in their classroom.

China business database

In order for Squeak use to be more

widespread, the supporting resources—books, tutorials, installers, etc.—would

need to be much more robust. Allen-Conn sees herself as the ‘buck-stops-here.’

element of Kay’s Squeak team: she has to make it meaningful for children: “I can

think lofty thoughts, but I also have to make this a viable tool.” (personal communi-

cation, Nov 2004). So, despite the fact that Allen-Conn herself remains encouraged,

Squeak’s presence simply will not grow of its own accord.

• The difficulty of sustaining technology once installed: Allen-Conn points out that

during the 1980s, the entire teaching staff at the Open School was trained to main-

tain and repair Apple computers. In the years after Apple’s involvement, the

parent-teacher community of the Open Charter School has taken it upon itself to

keep up its commitment to the sustainability of its technology investments. How

many schools can claim this kind of involvement?

• Technology policies in most schools and school districts are notoriously restrictive:

for support and administrative reasons, the typical pattern is that classroom or lab

computers are ‘locked down’ to prevent students from making modifications that

may put a burden on the tech support staff. So, installing software other than that

Chapter 7: Squeak’s Small but Mighty Roar 246

officially approved (typically Internet Explorer, Microsoft Office, and a small hand-

full of ‘educational’ applications), neither students nor teachers are at liberty to

install anything else—like Squeak. Going beyond these blanket restrictions would

likely entail getting approval at an administrative or even board level, something

that even companies with substantial marketing budgets struggle to do.

b2c china

Again, this

is an instance in which the general autonomy of the Open Charter School provides

a very atypical example.

• General awareness and mainstream trends: more generally, Squeak faces an uphill

battle simply by virtue of its distance from the mainstream (i.e. commercial soft-

ware and/or Unix-derived Internet culture). If educational computing is commonly

defined as learning to use a particular canonical list of application programs (web

browsers for research, ‘office’ software for document production, domain-specific

games or simulations for particular pedagogical ends), what are teachers or co-

ordinators to make of an environment that at times presents itself as programming

language, operating system, animation tool, simulation environment, or that bills

itself grandly as an “idea processor whose music is ideas?”

• Squeak is probably more complex than it needs to be: allowing a somewhat techno-

centric criticism here, it is fair to point out that the Squeak environment that one

faces after first launching the software are not immediately apparent: this undoubted-

edly presents a practical challenge to Squeak’s wider adoption. First, Squeak

doesn’t look or act quite like a Macintosh or Windows application, drawing as it

does on both older (and newer) user interface traditions; users must grapple with

how to interact with the mouse and onscreen objects before moving on to more

interesting things.

Email marketing in china

Second, there is substantial clutter in the Squeak environment;

much of the thirty-five years’ heritage of Squeak is actually in there (hundreds of

object classes, multiple interface frameworks, components of software no one has

actively used in years, and so on). The shrinking of the downloadable Squeak

Chapter 7: Squeak’s Small but Mighty Roar 247

“image” is the subject of the ongoing debate on the squeak-dev mailing list. 9 And finally,

the Morphic user interface framework itself, with its complete transparency and

direct-manipulation access to everything has the potential to overwhelm and

confuse new users.

Despite Squeak’s three-decade heritage, Etoys’ features, and the educational virtues

espoused by Kay and his colleagues, Squeak still remains an unknown quantity to main-

stream educators, even those who are active in the world of educational technology. Is this

likely to change? Not given the current landscape. There are simply no substantial forces

driving Squeak toward the educational mainstream, and there are many forces actively

resisting it. But we must keep in mind that the educational face of Squeak, of which Etoys is

emblematic, is not the whole story.

T H E S Q U E A K C O M M U N I T Y A N D I T S T R A J E C T O R I E S

What to make of Squeak? To whatever extent it represents a significant step forward or

the next iteration of a powerful tradition, it is also in many ways a non-starter, a tiny blip on

the vast landscape of (educational) technology. It seems as though one must grapple with

the history and heritage of the Dynabook ideal in order to fully appreciate Squeak; that with-

out this historical perspective, it appears as a bewildering and complex software

environment, inordinately challenging to sum up, let alone to treat as an instrument of practical

consequence.

China company email address

The hope of many in the Squeak community, presumably, is that Squeak

should gradually build its own momentum, and thereafter we will have a better appreciation

of its intellectual heritage.

But what is Squeak, exactly? Any precise answer to this question is partial, simply by

virtue of the multi-headedness of the project. I have so far focused mainly on the educa-

tional (Etoys) face of Squeak, but this is not manifest destiny. On the contrary; on the

9. The default downloadable Squeak image, as of version 3.8, is about 13 megabytes. There are various opinions about how small

an image could be while still being usable by the average person. One of the more extreme projects, called

Spoon has an

image of fewer than 100 kilobytes. See http://www.netjam.org/spoon/

Chapter 7: Squeak’s Small but Mighty Roar 248

Internet, an open-source project becomes what its users and developers make of it; there is

no ontological directive apart from the actual practice of the people who choose to make a

commitment of time and energy to a project.

China email sign up

In this sense, the lessons from Latour’s

Aramis are most apt: “There is no such thing as the essence of a project.

Only finished projects have an essence” (Latour, 1996, p. 48). But when is a project ever finished? In

Squeak’s case, the sheer flexibility of the system means that there are various sub-communi-

ties making headway in a number of different directions at once. Squeakland and Etoys

represent only one of these.

The Blue Plane and the Pink Plane

There are two orthogonal forces at work in the Squeak team, with which we have been

able to make two kinds of progress. These have most recently been articulated in Alan

Kay’s allusion to Arthur Koestler’s metaphor of progress in two planes: the incremental

improvement plane (which Alan calls the “pink” plane) and the paradigm shift (or “blue”)

plane.

– Dan Ingalls, 1997

The metaphor of planes of progress is drawn from Arthur Koestler’s The Act of Creation

(1964), one of Kay’s touchstones: Koestler’s model bears some resemblance to Thomas

Kuhn’s dynamics of paradigm shifts, though Koestler was concerned with creativity as a

psychological process rather than with the workings of institutional science. In any case,

these two ‘forces’ manifest themselves as two distinct but not wholly separate cultures

active in the Squeak community. The distinction can be characterized as follows. Increment-

tal improvement, or “pink plane” development, is the focus of a group of developers who

treat Squeak as a “better old thing,” as Kay might put it—that is, Squeak is a new, portable,

open-source Smalltalk-80 implementation. 

The efforts of this group go towards making it a

better implementation; improving the speed, cleaning up the codebase, putting in infra-

structure support for the development community (bug-report databases, versioning

systems and collaborative tools, etc.), streamlining and enhancing the user interface, and

adding various applications. This group, composed mainly of Smalltalk programmers who

have been working with the language for years, behaves much like the development

communities surrounding other open-source projects, like Linux or Apache. There is no

central leader of this sub-community; instead, there are a small number of key developers who

communicate primarily via the squeak-dev mailing list, coordinating the changes which peri-

odically constitute new version releases of the Squeak software, with incremental updates

appearing roughly twice per year. 10

The more revolutionary “blue plane” development appears to happen in a less open

environment. This force is represented more by Kay’s development team and colleagues.

China email lists provider

Prior to the v3.4 release of Squeak in 2003, this “Squeak Central” team—that is,

the group at

Apple and later Disney—made a number of substantial changes to Squeak (mainly notably

integrating the Morphic graphics framework, which was called a “blue plane” innovation at

the time), but since this time, they have not been particularly active in the online Squeak

development community.

Instead, they have been working “behind the curtain” on a

number of emerging innovations; notably, a new novice programming environment called

Tweak (which may also include the future of Etoys), and an immersive, multiparticipant 3D

environment called Croquet. These projects may potentially shift the focus of Squeak devel-

opment substantially, even to the point of threatening the relevance of some of the “pink

plane” development going on among the open-source community. 

Dan Ingalls notes:

To best understand the “blue” pull within the Squeak group, you need to

understand what we’re after. Our number one commitment is to an exquisite

personal computing environment. Imagine a system as immediate and tactile

as a sketch pad, in which you can effortlessly mingle writing, drawing, painting,

and all of the structured leverage of computer science. Moreover, imagine that

every aspect of that system is described in itself and equally amenable to exam-

nation and composition. Perhaps this system also extends out over the

Internet, including and leveraging off the work of others. You get the idea—it’s

the Holy Grail of computer science. All and everything. 

So if some new

approach comes along, that takes us closer to that ideal but at the cost of a

10. There is a complex history of leadership within the Squeak community, which I will not go into in detail. In 2005, a group called

The Squeak Foundation, composed of several influential developers from around the world, declared itself the (un)official stew-

ard of Squeak releases. See http://www.squeak.org

Chapter 7: Squeak’s Small but Mighty Roar 250

break with ST-80 tradition; we will probably take the new approach. (Ingalls

1997)

To put it in Eric Raymond’s terms, the Squeak project is simultaneously the “cathedral” and

the “bazaar.” Kay, Ingalls, and their cohort work in semi-private, releasing sizable new inno-

vations only now and then, while the evolutionary group works according to the bazaar

model. There is clearly some tension between the two groups, particularly when the “cathe-

dral” releases appear, and the evolutionary group must grapple with the changes in the

landscape. 11

Squeak Communities Today

After Kay’s team left Disney in 2001, there ceased to be a central commercial interest behind.

Squeak. Kay and Rose established the nonprofit Viewpoints Research Institute to act as the

official home for Squeak, but while Viewpoints has been partially funded in recent years by

Hewlett Packard, 12, the mainstream of Squeak development is no longer centred there. It is

instead spread globally, in a wide variety of different projects. The result is, as evidenced by

the potpourri of links on the main squeak.org website, that there are several public faces of

Squeak currently:

China business email database

1. The Viewpoints Research Institute, the nonprofit organization which is officially

behind Squeak, and which acts as an institutional focus for some of its development.

Viewpoints are the interface between the funding that Squeak may receive

from a company like HP and the notion of an open-source project owned and

beholden to no one.

Email lists providers in china

In practice, Viewpoints acts as the coordinating force behind

Squeakland.org and “blue-plane” development emerging from Kay and his immedi-

ate colleagues (e.g. the new Tweak authoring system, which purports to replace

portions of the Morphic interface).

11. This issue comes up periodically on the

squeak-dev mailing list. In September 2005, for instance, a discussion of the introduction-

on of a technology called “traits” as an alternative to the nearly 30-year-old hierarchy of object classes spawned much debate.