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Description

This error indicates that a `CHECK` constraint, specified by name, could not be found within the target table. It typically occurs when attempting to modify, drop, or reference a non-existent constraint, often due to a typo or the constraint being previously removed.

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Error Message

Check constraint '%s' is not found in the table.

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Known Causes

4 known causes

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Incorrect Constraint Name

The name of the `CHECK` constraint provided in the SQL statement does not exactly match an existing constraint in the table.

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Constraint Previously Removed

The `CHECK` constraint was already dropped from the table by a previous operation, but the current statement still references it.

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Operating on Wrong Table

The SQL statement is being executed against a table that does not contain the specified `CHECK` constraint, even if it exists in another table.

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Case Sensitivity Mismatch

The constraint name's casing in the SQL statement does not match the actual casing in the database, especially on case-sensitive operating systems.

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Solutions

3 solutions available

1. Re-create the Missing Check Constraint medium

The most direct solution is to add the missing check constraint back to the table.

1

Identify the exact name of the missing check constraint. The error message usually provides this (e.g., `'%s'`). If not, you'll need to infer it from your schema or recent changes.

2

Determine the definition of the check constraint (the condition it enforces). This is crucial for recreating it correctly. You might need to consult your application's code, database schema documentation, or historical schema changes.

3

Use an `ALTER TABLE` statement to add the check constraint back to the table. Replace `your_table_name`, `constraint_name`, and `your_condition` with your specific details.

ALTER TABLE your_table_name
ADD CONSTRAINT constraint_name CHECK (your_condition);

4

Verify that the constraint has been added successfully by querying the `information_schema.TABLE_CONSTRAINTS` or `information_schema.CHECK_CONSTRAINTS` tables.

SELECT CONSTRAINT_NAME, CONSTRAINT_TYPE
FROM information_schema.TABLE_CONSTRAINTS
WHERE TABLE_NAME = 'your_table_name' AND CONSTRAINT_SCHEMA = DATABASE();

SELECT CONSTRAINT_NAME, CHECK_CLAUSE
FROM information_schema.CHECK_CONSTRAINTS
WHERE TABLE_NAME = 'your_table_name' AND CONSTRAINT_SCHEMA = DATABASE();

2. Drop and Re-add the Table (if feasible) easy

For simpler schemas or development environments, dropping and recreating the table can resolve constraint issues.

1

Ensure you have a reliable backup of the table's data and its `CREATE TABLE` statement. This is a destructive operation.

2

Export the data from the table.

SELECT * FROM your_table_name INTO OUTFILE '/tmp/your_table_data.csv' FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\n';

3

Drop the existing table.

DROP TABLE your_table_name;

4

Re-create the table using its original `CREATE TABLE` statement, ensuring the check constraint is correctly defined within it. If the constraint was missed in the initial creation, add it here.

CREATE TABLE your_table_name (
    column1 datatype,
    column2 datatype,
    ...,
    CONSTRAINT constraint_name CHECK (your_condition)
);

5

Import the data back into the newly created table.

LOAD DATA INFILE '/tmp/your_table_data.csv' INTO TABLE your_table_name FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\n';

3. Investigate Schema Migration or Application Logic Errors advanced

This error often indicates a problem during schema changes or application updates.

1

Review recent schema migration scripts or application code that modifies the table structure. Look for any statements that might have intended to add or modify the check constraint but failed.

2

Examine application logs for errors related to database operations during the time the constraint might have gone missing.

3

If the constraint was removed intentionally as part of a controlled schema change, and the application logic no longer requires it, you may need to update your application or re-evaluate the schema design. If the constraint is still needed, proceed with Solution 1.

4

Consider using a version control system for your database schema to track changes and identify when and why the constraint was removed or never added.

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Related Errors

5 related errors

MySQL Error 3821: Check Constraint Missing