Table Creation and Management
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- Identify the table name and structure
- Commands used to create or modify database tables are called data definition language(DDL commands
- A Database Object is a defined self contained structure also called database tables
| Creating Tables | Description |
|---|---|
| CREATE TABLE | Creates a new table in the database. The user names the columns and identifies the type of data to be stored. To view a table, use the SQL*PLUS
command DESCRIBE. |
| Modifying Tables | |
| ALTER TABLE . . . ADD | Adds a column to a table. |
| ALTER TABLE . . . MODIFY | Changes a column size, datatype, or default value. |
| ALTER TABLE . . . DROP COLUMN | Deletes one column from a table |
| ALTER TABLE . . . SET UNUSED or SET UNUSED COLUMN | Marks a column for deletion at a latertime. |