|PostgreSQL Reference Manual - Volume 1 - SQL Language Reference|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 716 pages
RRP £32.00 ($49.95)
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3.5 Modifying Tables
When you create a table and you realize that you made a mistake, or the requirements of the application change, then you can drop the table and create it again. But this is not a convenient option if the table is already filled with data, or if the table is referenced by other database objects (for instance a foreign key constraint). Therefore PostgreSQL provides a family of commands to make modifications to existing tables. Note that this is conceptually distinct from altering the data contained in the table: here we are interested in altering the definition, or structure, of the table.
- Add columns,
- Remove columns,
- Add constraints,
- Remove constraints,
- Change default values,
- Change column data types,
- Rename columns,
- Rename tables.
All these actions are performed using the
command, q.v. for details beyond those given here.
|ISBN 0954612027||PostgreSQL Reference Manual - Volume 1 - SQL Language Reference||See the print edition|