ALTER#

ALTER TABKE statement allows you to change an existing table: add new columns or rename the table.

Add new fields to the table:

mngmt_ip - switch IP address in management VLAN
mngmt_vid - VLAN ID of management VLAN

Adding entries using ALTER TABLE:

new_db.db> ALTER table switch ADD COLUMN mngmt_ip text;
You're about to run a destructive command.
Do you want to proceed? (y/n): y
Your call!
Query OK, 0 rows affected
Time: 0.009s

new_db.db> ALTER table switch ADD COLUMN mngmt_vid integer;
You're about to run a destructive command.
Do you want to proceed? (y/n): y
Your call!
Query OK, 0 rows affected
Time: 0.010s

Now table looks like this (new fields are set to NULL):

new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+----------+-----------+
| mac            | hostname | model      | location          | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+----------+-----------+
| 0010.A1AA.C1CC | sw1      | Cisco 3750 | London, Green Str | <null>   | <null>    |
| 0020.A2AA.C2CC | sw2      | Cisco 3850 | London, Green Str | <null>   | <null>    |
| 0030.A3AA.C1CC | sw3      | Cisco 3750 | London, Green Str | <null>   | <null>    |
| 0040.A4AA.C2CC | sw4      | Cisco 3850 | London, Green Str | <null>   | <null>    |
| 0050.A5AA.C3CC | sw5      | Cisco 3850 | London, Green Str | <null>   | <null>    |
| 0060.A6AA.C4CC | sw6      | C3750      | London, Green Str | <null>   | <null>    |
| 0070.A7AA.C5CC | sw7      | Cisco 3650 | London, Green Str | <null>   | <null>    |
+----------------+----------+------------+-------------------+----------+-----------+
7 rows in set
Time: 0.034s