Data Definition and Data Manipulation Language-DDL & DML
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The document is a lecture outline by Md. Selim Hossain on Database Management Systems (DBMS), focusing on Data Definition Language (DDL) and Data Manipulation Language (DML) as sub-languages of SQL. It details various SQL statements, including CREATE, ALTER, DROP, TRUNCATE for DDL, and INSERT, UPDATE, DELETE for DML, explaining their functions and example usages. Additionally, it distinguishes between commands that modify database structures and those that manipulate the data within those structures.
![CREATE TABLE statement
• A commonly used CREATE command is the
CREATE TABLE command. The typical usage is:
CREATE TABLE [table name] ( [column
definitions] ) [table parameters]
Md. Selim Hossain 8](https://image.slidesharecdn.com/finaldatabaseworking-170320202709/85/Data-Definition-and-Data-Manipulation-Language-DDL-DML-8-320.jpg)
Data Definition and Data Manipulation Language-DDL & DML
- 1. About Me Md. Selim Hossain Lecturer Dept. of CSE UTTARA UNIVERSITY House#05, Section#06, Road#15, Uttara, Dhaka-1230. Md. Selim Hossain 1
- 3. Topics for Today Md. Selim Hossain 3
- 4. Data Definition Language (DDL) Data Manipulation Language (DML) Md. Selim Hossain 4
- 5. SQL statements are divided into two major categories: Data Definition Language (DDL) and Data Manipulation Language (DML). Md. Selim Hossain 5
- 6. Data Definition Language (DDL) • DDL statements are used to build and modify the structure of tables and other objects in the database. • DDL is a sub-language of SQL used to create and manipulate objects in a database. DDL provides the following statements to manipulate the object in database: CREATE, ALTER, DROP, TRUNCATE, RENAME Md. Selim Hossain 6
- 7. Data Definition Language (DDL) CREATE statement (to create objects in the database): • The CREATE statement in SQL creates a component in a relational database management system (RDBMS). • The CREATE command is used to establish a new database, table, index, or stored procedure. Md. Selim Hossain 7
- 8. CREATE TABLE statement • A commonly used CREATE command is the CREATE TABLE command. The typical usage is: CREATE TABLE [table name] ( [column definitions] ) [table parameters] Md. Selim Hossain 8
- 9. CREATE TABLE statement • An example of statement to create a table named employees with a few columns is: Md. Selim Hossain 9
- 10. CREATE TABLE statement Note: The full structure of table can be viewed with the DESC command. DESC <TABLE_NAME> Md. Selim Hossain 10
- 11. DROP statement • The DROP statement destroys an existing database, table, index, or view. • A DROP statement in SQL removes a component from a relational database management system (RDBMS). • Drop statement is used to delete an existing object from the database. It can also be used to delete any column from a table. Md. Selim Hossain 11
- 12. DROP statement • The DROP statement is distinct from the DELETE and TRUNCATE statements, in that DELETE and TRUNCATE do not remove the table itself. For example, a DELETE statement might delete some (or all) data from a table while leaving the table itself in the database, whereas a DROP statement removes the entire table from the database. Md. Selim Hossain 12
- 13. DROP statement Md. Selim Hossain 13
- 14. DROP statement The typical usage is simply: • For example, the command to drop a table named employees is: Md. Selim Hossain 14
- 15. ALTER statement • The ALTER statement modifies an existing database object or, Alter statement is used to modify the structure of an existing object. • Below alteration can be done on a table: o Addition of new columns o Deletion of existing columns o Changing the data type of columns o Changing the size of columns Md. Selim Hossain 15
- 16. ALTER statement • The typical usage is: Md. Selim Hossain 16
- 17. ALTER statement Note: To change the data type of a column, the column must be empty. Md. Selim Hossain 17
- 18. RENAME statement Rename statement is used to rename an existing object from a database Md. Selim Hossain 18
- 19. RENAME statement • The RENAME statement is used to rename a database table. Md. Selim Hossain 19
- 20. TRUNCATE statement • The TRUNCATE statement is used to delete all data from a table. It's much faster than DELETE. Md. Selim Hossain 20
- 21. Data Manipulation Language (DML) • A data manipulation language (DML) is a family of syntax elements similar to a computer programming language used for selecting, inserting, deleting and updating data in a database. Md. Selim Hossain 21
- 22. Data Manipulation Language (DML) DML also known as query language Two classes of languages Procedural – user specifies what data is required and how to get those data Nonprocedural – user specifies what data is required without specifying how to get those data Md. Selim Hossain 22
- 23. Data Manipulation Language (DML) • DML is a sub-language of SQL. It is used to manipulate the data stored in a table. • DML provides the following statements for data manipulation: INSERT UPDATE DELETE Md. Selim Hossain 23
- 24. Data Manipulation Language (DML) INSERT Statement • INSERT statement is used to insert a new record into a table. Md. Selim Hossain 24
- 25. Data Manipulation Language (DML) INSERT Statement • Example • Consider a table 'EMP' having columns named EMPNO, NAME, SAL and JOB. We can be used the below INSERT statement to insert a new record to it. Md. Selim Hossain 25
- 26. UPDATE Statement • Update statement is used to update an existing record in a table. Md. Selim Hossain 26
- 27. UPDATE Statement • If the where clause of omitted, the statement will update all the values in the particular column. Md. Selim Hossain 27
- 28. UPDATE Statement • Note: IS NULL is used for assignment and =NULL is used to recognize. Md. Selim Hossain 28
- 29. DELETE Statement • Delete Statement is used to delete records from a table. Md. Selim Hossain 29
- 30. DELETE Statement Md. Selim Hossain 30
- 31. DELETE Statement • Below statement will delete all records from the table. Md. Selim Hossain 31
- 32. Md. Selim Hossain Thank you 32