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How to prevent duplicate INSERT in MySQL?
For this, you can use UNIQUE INDEX −
alter table yourTableName ADD UNIQUE INDEX(yourColumnName1, yourColumnName2,....N);
Let us first create a table −
mysql> create table DemoTable -> ( -> Value1 int, -> Value2 int -> ); Query OK, 0 rows affected (0.55 sec)
Following is the query to add unique index −
mysql> alter table DemoTable ADD UNIQUE INDEX(Value1, Value2); Query OK, 0 rows affected (0.54 sec) Records: 0 Duplicates: 0 Warnings: 0
Insert some records in the table using insert command −
Note − Use the INSERT IGNORE command rather than the INSERT command. If a record doesn't duplicate an existing record, then MySQL inserts it as usual. If the record is a duplicate, then the IGNORE keyword tells MySQL to discard it silently without generating an error.
mysql> insert ignore into DemoTable values(10,20); Query OK, 1 row affected (0.14 sec) mysql> insert ignore into DemoTable values(10,20); Query OK, 0 rows affected, 1 warning (0.10 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
Output
This will produce the following output −
+--------+--------+ | Value1 | Value2 | +--------+--------+ | 10 | 20 | +--------+--------+ 1 row in set (0.00 sec)
Updated on: 30-Jun-2020
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