SQL

This presentation will cover:

A Brief History of DBMS View in databaseMySQL installation

SQL – DBMS History

DBMS History

The IBM’s System/R was not the first DBMS. The first to market was Relational Software's product named Oracle

The second was Relational Technology's Ingres.

IBM then released improved products in 1982 named SQL/DS and DB2. Oracle and DB2 in nth generation forms while the Ingres technology was bought by Computer Associates.

SQL - Standards SQL is a open language without corporate ownership.

The ANSI-SQL (American National Standards Institute) group has published three standards over the years:

SQL89 (SQL1)SQL92 (SQL2)SQL99 (SQL3)

The majority of the language has not changed through these updates.

The SQL standard from ANSI is considered the "pure" SQL and called ANSI-SQL.

SQL – Enhanced features

Every DBMS vendor wants their products to be different. So most products offers extra features, these additions are generally not compatible with competitor's SQL products.

It is always safest to stick with pure SQL

The enhancements are not all bad because these extensions are very useful.

For example, most DBMS sold today have an automatic way to assign a serial number feature since serial numbering is so common. However, the method of implementation is not uniform.

What is a View? In SQL, a VIEW is a virtual relation based on the res

ult-set of a SELECT statement.

A view contains rows and columns, just like a real table. The fields in a view are fields from one or more real tables in the database. In some cases, we can modify a view and present the data as if the data were coming from a single table.

Syntax:

CREATE VIEW view_name ASSELECT column_name(s)FROM table_nameWHERE condition

SQL – Relations, Tables & Views

When we say Relation, it could be a Table or a View. There are three kind of relations:

1. Stored relations tables

We sometimes use the term “base relation” or “base table”

2. Virtual relations views

3. Temporary results

SQL – Create View

Example: Create a view with title and year and made by Paramount studio.

Movie (title, year, length, inColor, studioName, producerC#)

CREATE VIEW ParamountMovie ASSELECT title,yearFROM MovieWHERE studioName = ‘Paramount’;

SQL – Querying View A view could be used from inside a query, a stored proc

edure, or from inside another view. By adding functions, joins, etc., to a view, it allows us to present exactly the data we want to the user.

SELECT titleFROM ParamountMovieWHERE year = ‘1979’;

Have same result asSELECT titleFROM MovieWHERE studioName = ‘Paramount’ AND year = ‘1

979’;

View

Table

SQL - Querying View con’t

Query involving both view and table

SELECT DISTINCT starName

FROM ParamountMovie, StarsIn

WHERE title = movieTitle AND year = movieYear;

Table

View

SQL - Querying View exampleMovie (title, year, length, inColor, studioName, producerC#)MovieExec (name, address, cert#, netWorth)

CREATE VIEW MovieProd AS SELECT title, nameFROM Movie, MovieExecWHERE producerC# = cert#;

SELECT nameFROM MovieProdWHERE title = ‘Gone With the Wind’;

Same result as query from tablesSELECT nameFROM Movie, MovieExecWHERE producerC# = cert# AND title = ‘The War Of the World’;

SQL - Renaming Attributes in View

Sometime, we might want to distinguish attributes by giving the different name.

CREATE VIEW MovieProd (movieTitle, prodName) AS

SELECT title, name

FROM Movie, MovieExec

WHERE producerC# = cert#;

SQL - Modifying View

When we modify a view, we actually modify a table through a view. Many views are not updateable. Here are rules have been defined in SQL for updateable views:

selecting (SELECT not SELECT DISTINCT) some attributes from one relation R (which may itself be an updateable view)

The WHERE clause must not involve R in a subquery.

The list in the SELECT clause must include enough attributes that will allow us to insert tuples into the view as well as table. All other attributes will be filled out with NULL or the proper default values.

SQL – Modifying View (INSERT)

INSERT INTO ParamountMovieVALUES (‘Star Trek’, 1979);To make the view ParamountMovie updateable, we need to add a

ttribute studioName to it’s SELECT clause because it makes more sense if the studioName is Paramount instead of NULL.

CREATE VIEW ParamountMovie AS SELECT studioName, title, yearFROM MovieWHERE studioName = ‘Paramount’;

ThenINSERT INTO ParamountMovieVALUES (‘Paramount’, ‘Star Trek’, 1979);

Title year length inColor studioName producerC#‘Star Trek’ 1979 0 NULL ‘Paramount’ NULL

SQL - Modifying View (DELETE)

Suppose we wish to delete all movies with “Trek” in their title from the updateable view ParamountMovie.

DELETE FROM ParamountMovieWHERE title LIKE ‘%Trek%’;

It is turned into the base table delete

DELETE FROM MovieWHERE title LIKE ‘%Trek%’ AND studioName = ‘Para

mount’;

SQL - Modifying View (UPDATE)

UPDATE from an updateable viewUPDATE ParamountMovieSET year = 1979WHERE title = ‘Star Trek the Movie’;

It is turned into the base table update

UPDATE MovieSET year = 1979WHERE title = ‘Star Trek the Movie’ AND studioName

= ‘Paramount’;

SQL – View (DROP)

DROP view: All views can be dropped, whether or not the view is updateable.

DROP VIEW ParamountMovie;

DROP VIEW does not affect any tuples of the underlying relation (table) Movie.

However, DROP TABLE will delete the table and also make the view ParamountMovie unusable.

DROP TABLE Movie

SQL - Download MySQL

Go to http://dev.mysql.com/downloads/ and download:

MySQL (Windows User / version 4.1.10a, 5.0.2-alpha has bug that keep shutting down the service)

MySQL Administrator MySQL Query Browser

SQL – Install MySQL During the installation –

you can <“Skip Sing-Up”> to fast installation Will run Configuration Wizard right after installation automaticall

y If the service won’t start, press <cancel>, then run Configuratio

n Wizard manually again Run MySQL Server Instance Config Wizard from windo

ws menu – use default setting unless you know what you are doing Modify Security Setting (option: you can start service without d

oing this) Execute

If there is an error, try press <back> to go back, then press <next> to <execute> again

TCP / IP Networking – Try different port number if you are using networking.

SQL - MySQL Administrator

MySQL Administrator come with MySQL System Tray Monitor allow you to configure your server

Run MySQL Administrator –For the first time, you may not have “Stored c

onnection,” you can <Add new Connection> and give the Connection name.

Server Host: type “localhost” If you don’t use networking

SQL - MySQL Query Browser

Run MySQL Query BrowserGive a name for the Default Schema

Schema means Database instanceYou can type command line into the top box

or right Click on schemata to create new table

SQL - Bibliography

First Course In Database Systems, Jeffery D. Ullman and Jennifer Widom,1997 Prentice Hall, Inc.

http://mysql.com