Difference between revisions of "Table Creation and Management"

Revision as of 23:32, 29 September 2017

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.

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-;Create a new table with the CREATE TABLE command
-;Use a subquery to create a new table
-;Add a column to an existing table
-;Modify the definition of a column in an existing table
-;Delete a column from an existing table
-;Mark a column as unused and then delete it later
-;Rename a table
-;Truncate a table
-;Drop a table