Sql Guide (Speedy Study Guides). Speedy Publishing

      

      What is SQL?

      SQL is Structured Query Language, which is a computer language for storing, manipulating and retrieving data stored in relational database.

      SQL is the standard language for Relation Database System. All relational database management systems like MySQL, MS Access, Oracle, Sybase, Informix, postgres and SQL Server use SQL as standard database language.

      Also, they are using different dialects, such as:

      MS SQL Server using T-SQL, Oracle using PL/SQL, MS Access version of SQL is called JET SQL (native format), etc

       SQL

      • Allows users to access data in relational database management systems.

      • Allows users to describe the data.

      • Allows users to define the data in database and manipulate that data.

      • Allows embedding within other languages using SQL modules, libraries & precompilers.

      • Allows users to create and drop databases and tables.

      • Allows users to create view, stored procedure, functions in a database.

      • Allows users to set permissions on tables, procedures, and views

      RDBMS

      RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL and for all modern database systems like MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.

      A Relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd.

      Table

      The data in RDBMS is stored in database objects called tables. The table is a collection of related data entries and it consists of columns and rows.

      Remember, a table is the most common and simplest form of data storage in a relational database.

      Field

      Every table is broken up into smaller entities called fields. The fields in the CUSTOMERS table consist of ID, NAME, AGE, ADDRESS and SALARY.