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❮ Sqlite Indexed By Sqlite Insert ❯

SQLite Alter Command

SQLite's ALTER TABLE command modifies existing tables without performing a full dump and reloading of the data. You can use the ALTER TABLE statement to rename tables and add additional columns to existing tables.

In SQLite, the ALTER TABLE command does not support other operations besides renaming tables and adding columns to existing tables.

Syntax

The basic syntax for renaming an existing table with ALTER TABLE is as follows:

ALTER TABLE database_name.table_name RENAME TO new_table_name;

The basic syntax for adding a new column to an existing table with ALTER TABLE is as follows:

ALTER TABLE database_name.table_name ADD COLUMN column_def...;

Example

Suppose our COMPANY table has the following records:

ID          NAME        AGE         ADDRESS     SALARY
----------  ----------  ----------  ----------  ----------
1           Paul        32          California  20000.0
2           Allen       25          Texas       15000.0
3           Teddy       23          Norway      20000.0
4           Mark        25          Rich-Mond   65000.0
5           David       27          Texas       85000.0
6           Kim         22          South-Hall  45000.0
7           James       24          Houston     10000.0

Now, let's try to rename the table using the ALTER TABLE statement as follows:

sqlite> ALTER TABLE COMPANY RENAME TO OLD_COMPANY;

The above SQLite statement will rename the COMPANY table to OLD_COMPANY. Now, let's try to add a new column to the OLD_COMPANY table as follows:

sqlite> ALTER TABLE OLD_COMPANY ADD COLUMN SEX char(1);

Now, the COMPANY table has changed, and the output using the SELECT statement is as follows:

ID          NAME        AGE         ADDRESS     SALARY      SEX
----------  ----------  ----------  ----------  ----------  ---
1           Paul        32          California  20000.0
2           Allen       25          Texas       15000.0
3           Teddy       23          Norway      20000.0
4           Mark        25          Rich-Mond   65000.0
5           David       27          Texas       85000.0
6           Kim         22          South-Hall  45000.0
7           James       24          Houston     10000.0

Note that the newly added column is filled with NULL values.

❮ Sqlite Indexed By Sqlite Insert ❯