DB2 - Structured Query Language(SQL) Types
SQL (Structured Query Language) is a language designed specifically for communicating with databases and is a powerful tool for manipulating data. It is the standard query language for relational database management systems (RDBMS).
It is a database-independent language that allows you to query data and to perform CRUD (Create, Update, and Delete) operations. SQL is easy to learn. The statements are all made up of descriptive English words.
SQL consists of three sublanguages as follows:
-
DDL: Data Definition Language
DML: Data Manipulation Language
DCL: Data Control Language
DDL (Data Definition Language) creates and maintains physical data structures using the following statements:
- Create: Creating the objects.
- Alter: Changing the characteristics of the existing objects.
- Drop: Deleting the objects.
DML (Data Manipulation Language) perform the following operations:
- Insert
- Update
- Delete
- Retrieval (Simple, multiple columns, all columns)
- Sorting the retrieved data
- Filtering the data
- Concatenation
- Using alias
- Removing duplicates
- Functions
- Grouping
- Subquery
- Join
- Union
DCL (Data Control Language) perform the following operations:
- Grant
- Revoke
Database Security is managed through the SQL GRANT and REVOKE statements.
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