Can t write duplicate key in table user?

Can t write duplicate key in table user?

The most likely you already have a constraint with the name iduser or idcategory in your database. Just rename the constraints if so. Constraints must be unique for the entire database, not just for the specific table you are creating/altering. Change the Foreign key name in MySQL.

How do I drop a constraint in MySQL?

MySQL – How to DROP CONSTRAINT in MySQL?

1. ALTER TABLE `table_name` DROP FOREIGN KEY `id_name_fk`;
2. ALTER TABLE `table_name` DROP INDEX `id_name_fk`;
3. SET FOREIGN_KEY_CHECKS=0;
4. SET FOREIGN_KEY_CHECKS=1;

How can I see all constraints in MySQL?

select COLUMN_NAME, CONSTRAINT_NAME, REFERENCED_COLUMN_NAME, REFERENCED_TABLE_NAME from information_schema. KEY_COLUMN_USAGE where TABLE_NAME = ‘yourTableName’; To display all constraints on a table, implement the above syntax.

Can not add foreign key constraint?

Reasons you may get a foreign key constraint error: You are not using InnoDB as the engine on all tables. The types of the columns are not the same (exception is the column on the referencing table can be nullable even if it is not nullable on the referenced table).

How do I rename a table in MySQL workbench?

The syntax to rename a table in MySQL is: ALTER TABLE table_name RENAME TO new_table_name; table_name. The table to rename.

Is foreign key can be null?

Short answer: Yes, it can be NULL or duplicate. I want to explain why a foreign key might need to be null or might need to be unique or not unique. First remember a Foreign key simply requires that the value in that field must exist first in a different table (the parent table). That is all an FK is by definition.

How do you remove constraints?

Using SQL Server Management Studio

1. In Object Explorer, expand the table with the check constraint.
2. Expand Constraints.
3. Right-click the constraint and click Delete.
4. In the Delete Object dialog box, click OK.

How do I view constraints in SQL?

Using SQL Server Management Studio

1. In the Object Explorer, right-click the table containing the check constraint and select Design.
2. On the Table Designer menu, click Check Constraints….
3. In the Check Constraints dialog box, under Selected Check Constraint, select the constraint you wish to edit.

How do I make a foreign key column in phpmyadmin?

To do that follow the steps.

1. Open table structure. ( 2nd tab)
2. See the last column action where multiples action options are there. Click on Index, this will make the column indexed.
3. Open relation view and add foreign key constraint.

Can we rename table in MySQL?

Why do I have duplicate key in MySQL?

This can also arise in connection with a bug in certain versions of Percona Toolkit’s online-schema-change tool. To mutate a large table, pt-osc first creates a duplicate table and copies all the records into it.

Can You duplicate a constraint name in MySQL?

According to: MySQL error 1022 when creating table You can’t have a foreign key constraint name duplicated over the entire model. Just rename The constraints names differently and your problem is solved…

Why is MySQL unable to write foreign key?

That is, when the CREATE TABLE statement (as posted by OP) is processed, InnoDB is attempting to create both the index defined on User_id_fk, and the index required for the foreign key. And those two indexes are “duplicates” of each other.

Can you have two foreign keys with the same name?

The Database Schema Cannot have two or more FOREIGN KEY with same name. I change all FOREIGN KEYS to different names in my DB Schema then it works… Either that, or remove the foreign key constraint from the table definition, and add that in a separate ALTER TABLE statement.