Data Definition and Data Manipulation Language-DDL & DML
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DDL statements are used to build and modify the structure of tables and other objects in the database and 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.
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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