Datawarehouse Architect

The Data Definition Language (DDL) part of SQL permits database tables to be created or deleted. We can also define indexes (keys), specify links between tables, and impose constraints between database tables.  The most important DDL statements in SQL are:  CREATE TABLE - creates a new database table  ALTER TABLE - alters (changes) a database table  DROP TABLE - deletes a database table  CREATE INDEX - creates an index (search key)  DROP INDEX - deletes an index

SQL (Structured Query Language) is a syntax for executing queries. But the SQL language also includes a syntax to update, insert, and delete records. These query and update commands together form the Data Manipulation Language (DML) part of SQL:  SELECT - extracts data from a database table   UPDATE - updates data in a database table    DELETE - deletes data from a database table    INSERT INTO - inserts new data into a database table

SQL is a standard computer language for accessing and manipulating databases.   What is SQL? • SQL stands for Structured Query Language  • SQL allows you to access a database  • SQL is an ANSI standard computer language  • SQL can execute queries against a database  • SQL can retrieve data from a database  • SQL can insert new records in a database  • SQL can delete records from a database  • SQL can update records in a database  • SQL is easy to learn What is SQL? SQL is a Standard - BUT.... SQL is an ANSI (American National Standards Institute) standard computer language for accessing and manipulating database systems. SQL statements are used to retrieve and update data in a database. SQL works with database programs like MS Access, DB2, Informix, MS SQL Server, Oracle, Sybase, etc. Unfortunately, there are many different versions of the SQL language, but to be in compliance with th...