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UPDATE
Оператор UPDATE используется для изменения существующей записи таблицы.
Обычно, UPDATE используется вместе с оператором WHERE, чтобы уточнить, какую именно запись необходимо изменить.
С помощью UPDATE можно заполнить новые столбцы в таблице.
Например, добавить IP-адрес для коммутатора sw1:
new_db.db> UPDATE switch set mngmt_ip = '10.255.1.1' WHERE hostname = 'sw1';
Query OK, 1 row affected
Time: 0.009s
Теперь таблица выглядит так:
new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.A1AA.C1CC | sw1 | Cisco 3750 | London, Green Str | 10.255.1.1 | <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: 0.035s
Аналогичным образом можно изменить и номер VLAN:
new_db.db> UPDATE switch set mngmt_vid = 255 WHERE hostname = 'sw1';
Query OK, 1 row affected
Time: 0.009s
new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.A1AA.C1CC | sw1 | Cisco 3750 | London, Green Str | 10.255.1.1 | 255 |
| 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: 0.037s
Можно изменить несколько полей за раз:
new_db.db> UPDATE switch set mngmt_ip = '10.255.1.2', mngmt_vid = 255 WHERE hostname = 'sw2'
Query OK, 1 row affected
Time: 0.009s
new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.A1AA.C1CC | sw1 | Cisco 3750 | London, Green Str | 10.255.1.1 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 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: 0.033s
Чтобы не заполнять поля mngmt_ip и mngmt_vid вручную, заполним
остальное из файла update_fields_in_testdb.txt (команда source update_fields_in_testdb.txt):
UPDATE switch set mngmt_ip = '10.255.1.3', mngmt_vid = 255 WHERE hostname = 'sw3';
UPDATE switch set mngmt_ip = '10.255.1.4', mngmt_vid = 255 WHERE hostname = 'sw4';
UPDATE switch set mngmt_ip = '10.255.1.5', mngmt_vid = 255 WHERE hostname = 'sw5';
UPDATE switch set mngmt_ip = '10.255.1.6', mngmt_vid = 255 WHERE hostname = 'sw6';
UPDATE switch set mngmt_ip = '10.255.1.7', mngmt_vid = 255 WHERE hostname = 'sw7';
После загрузки команд таблица выглядит так:
new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.A1AA.C1CC | sw1 | Cisco 3750 | London, Green Str | 10.255.1.1 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 0030.A3AA.C1CC | sw3 | Cisco 3750 | London, Green Str | 10.255.1.3 | 255 |
| 0040.A4AA.C2CC | sw4 | Cisco 3850 | London, Green Str | 10.255.1.4 | 255 |
| 0050.A5AA.C3CC | sw5 | Cisco 3850 | London, Green Str | 10.255.1.5 | 255 |
| 0060.A6AA.C4CC | sw6 | C3750 | London, Green Str | 10.255.1.6 | 255 |
| 0070.A7AA.C5CC | sw7 | Cisco 3650 | London, Green Str | 10.255.1.7 | 255 |
+----------------+----------+------------+-------------------+------------+-----------+
7 rows in set
Time: 0.038s
Теперь предположим, что sw1 был заменен с модели 3750 на модель 3850. Соответственно, изменилось не только поле модель, но и поле MAC-адрес.
Внесение изменений:
new_db.db> UPDATE switch set model = 'Cisco 3850', mac = '0010.D1DD.E1EE' WHERE hostname = 'sw1';
Query OK, 1 row affected
Time: 0.009s
Результат будет таким:
new_db.db> SELECT * from switch;
+----------------+----------+------------+-------------------+------------+-----------+
| mac | hostname | model | location | mngmt_ip | mngmt_vid |
+----------------+----------+------------+-------------------+------------+-----------+
| 0010.D1DD.E1EE | sw1 | Cisco 3850 | London, Green Str | 10.255.1.1 | 255 |
| 0020.A2AA.C2CC | sw2 | Cisco 3850 | London, Green Str | 10.255.1.2 | 255 |
| 0030.A3AA.C1CC | sw3 | Cisco 3750 | London, Green Str | 10.255.1.3 | 255 |
| 0040.A4AA.C2CC | sw4 | Cisco 3850 | London, Green Str | 10.255.1.4 | 255 |
| 0050.A5AA.C3CC | sw5 | Cisco 3850 | London, Green Str | 10.255.1.5 | 255 |
| 0060.A6AA.C4CC | sw6 | C3750 | London, Green Str | 10.255.1.6 | 255 |
| 0070.A7AA.C5CC | sw7 | Cisco 3650 | London, Green Str | 10.255.1.7 | 255 |
+----------------+----------+------------+-------------------+------------+-----------+
7 rows in set
Time: 0.049s