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- MySQL - Make an existing Field Unique 7 answers
MySQL - 创建一个现有的Field Unique 7答案
+-----+--------------+--------+-----------+
| id | a_no | status | req_date |
+-----+--------------+--------+-----------+
| 1 | 6019-6039120 | 0 |2015-03-01 |
| 2 | 6019-6039120 | 0 |2015-03-01 |
| 4 | 6019-6039120 | 0 |2015-03-02 |
| 5 | 6019-6039121 | 0 |2015-03-02 |
| 6 | 6019-6039134 | 0 |2015-03-02 |
| 7 | 6019-6039134 | 0 |2015-03-02 |
| 8 | 6019-6039120 | 0 |2015-03-03 |
| 9 | 6019-6039129 | 0 |2015-03-03 |
| 10 | 6019-6039145 | 0 |2015-03-04 |
| 11 | 6019-6039167 | 0 |2015-03-04 |
+-----+--------------+--------+-----------+
This is my table structure, as you can see id=1 and id=2 have a same data. How to prevent the same data to insert into my table?
这是我的表结构,因为您可以看到id = 1和id = 2具有相同的数据。如何防止相同的数据插入我的表?
1 个解决方案
#1
Add a unique constraint/index:
添加唯一约束/索引:
create unique index idx_table_3 on table(a_no, status, req_date);
This will prevent duplicates in the table. An attempt to insert duplicates will result in an error.
这样可以防止表中的重复。尝试插入重复项将导致错误。
#1
Add a unique constraint/index:
添加唯一约束/索引:
create unique index idx_table_3 on table(a_no, status, req_date);
This will prevent duplicates in the table. An attempt to insert duplicates will result in an error.
这样可以防止表中的重复。尝试插入重复项将导致错误。