記事の内容
概要
DROP分は、データベース・テーブル、インデックス・ビュー・などのオブジェクトを削除できます。
DROP
記述
DROP DATABASE データベース名;
【DB一覧】
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| laravel |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
6 rows in set (0.01 sec)
mysql> DROP DATABASE test;
Query OK, 1 row affected (0.01 sec)
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| laravel |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.01 sec)指定テーブル削除
DROP(テーブル削除)
記述
DROP TABLE テーブル名;
【テーブル一覧】
mysql> SHOW TABLES;
+-----------------------+
| Tables_in_testDB |
+-----------------------+
| cache |
| cache_locks |
| failed_jobs |
| job_batches |
| jobs |
| migrations |
| password_reset_tokens |
| sessions |
| test |
| users |
+-----------------------+
10 rows in set (0.01 sec)
【testテーブル削除】
mysql> DROP TABLE test;
Query OK, 1 row affected (0.01 sec)
【テーブル一覧】
mysql> SHOW TABLES;
+-----------------------+
| Tables_in_testDB |
+-----------------------+
| cache |
| cache_locks |
| failed_jobs |
| job_batches |
| jobs |
| migrations |
| password_reset_tokens |
| sessions |
| users |
+-----------------------+
9 rows in set (0.01 sec)インデックス削除
DROP(テーブル削除)
記述
DROP INDEX インデックス名 ON テーブル名;
【テーブル一覧】
mysql> SHOW INDEX FROM users;
+-------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression |
+-------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
| users | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | | | YES | NULL |
| users | 1 | user_name | 1 | name | A | 0 | NULL | NULL | YES | BTREE | | | YES | NULL |
+-------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
2 rows in set (0.00 sec)
【testテーブル削除】
mysql> DROP INDEX user_name ON users;
Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0
【テーブル一覧】
mysql> SHOW INDEX FROM users;
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
| users | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | | | YES | NULL |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
1 row in set (0.01 sec)
ビュー削除
DROP(ビュー削除)
記述
DROP VIEW ビュー名;
【テーブル一覧】
mysql> SHOW TABLES;
+--------------------------+
| Tables_in_test_db |
+--------------------------+
| departments |
| employees |
| employee_department_view |
+--------------------------+
3 rows in set (0.01 sec)
【ビュー削除】
mysql> DROP VIEW employee_department_view;
Query OK, 0 rows affected (0.01 sec)
【テーブル一覧】
mysql> SHOW TABLES;
+--------------------------+
| Tables_in_test_db |
+--------------------------+
| departments |
| employees |
+--------------------------+
2 rows in set (0.01 sec)