SQL for Data Manipulation

The CREATE statements of the previous section built the database StudentAttendance with its three relations — STUDENT, GUARDIAN and ATTENDANCE. But creating a table brings only its structure into existence: the columns, their data types and their constraints. The table itself contains no data at that point.

Filling and maintaining the data is the job of SQL's data manipulation statements:

• To populate records in a table, the INSERT statement is used.
• Records in a table can likewise be deleted or updated using SQL data manipulation statements.

Data manipulation using a database means any of four operations:

1. Retrieval (access) of existing data,
2. Insertion of new data,
3. Removal of existing data,
4. Modification of existing data in the database. …