Duplicate entry 'XXX' for key 'XXX.PRIMARY' solution.

Error in mysql insert: Duplicate entry 'XXX' for key 'XXX.PRIMARY'

An error occurred while inserting data today

com.jfinal.plugin.activerecord.ActiveRecordException:com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException:Duplicate entry 'xxxxxx' for key 'xxxx.PRIMARY'

On the Internet, it said that the primary key conflicted, but the database did not. After clearing all the data, or deleting the table, the same error was reported after rebuilding.
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Final result scheme:

1. Option 1: Set the primary key to auto-increment, suitable for the primary key to be int type (my primary key is varchar)
2. Option 2: Change insert into table name() values(); to: insert ignore into table name() values(); (problem solving)

MySQL provides Ignore to avoid repeated insertion of data.
IGNORE :
If there is a record that causes a unique key conflict, the record will not be inserted into the database.

MySQL INSERT IGNORE Please go to: MySQL INSERT IGNORE

Reason: This is because a unique index is set for the corresponding field in the table. When we perform logical deletion, there is no real deletion, but it is only marked as deleted.
When we add it again, becauseThere is a limitation of unique index, which makes us unable to add successfully, so an error is reported.
Solution 1:
If allowed, remove the unique index limitation of this field in the database, so that the backend can perform logical deletion,Even if the field value of the record marked for deletion is equal to the field value when adding, because there is no unique index restriction, it can be added normally
Solution 2:
It is not necessary to remove the unique index restriction in the database, but when the back-endWhen developing the delete operation, the SQL statement for physical deletion (real deletion) is executed instead of logical deletion. At the same time, the backend uses logical judgment to query whether the same number exists in the database. If it exists, it is not allowed.Add, if it doesn't exist, you can add it

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