[MySQL-kit] Fix CHECK constraint column case mismatch causing MariaDB push failure

[karthik-idikuda]

Problem

drizzle-kit push exits with code 1 on MariaDB databases containing CHECK constraints. The issue occurs during schema introspection ("Pulling schema from database...").

Root Cause

The CHECK constraints introspection query selects columns with lowercase names:

SELECT tc.table_name, tc.constraint_name, cc.check_clause FROM ...

But the result mapping reads uppercase keys:

const constraintName = checkConstraintRow['CONSTRAINT_NAME'];
const constraintValue = checkConstraintRow['CHECK_CLAUSE'];
const tableName = checkConstraintRow['TABLE_NAME'];

On MySQL, information_schema returns uppercase column names regardless of the query, so this works. On MariaDB (with mysql2 driver), result keys match the case used in the SQL query - returning lowercase keys. This mismatch produces undefined values, which crash when accessing tableInResult.checkConstraint.

Fix

1. Add explicit AS aliases to the SELECT columns so they always return uppercase keys regardless of the database engine:

SELECT
    tc.table_name AS TABLE_NAME,
    tc.constraint_name AS CONSTRAINT_NAME,
    cc.check_clause AS CHECK_CLAUSE
FROM ...

2. Uncomment the tableInResult guard (was commented out) to safely skip CHECK constraints for tables not in the result set (e.g., filtered tables), preventing potential runtime crashes.

Reproduction

1. Use MariaDB (e.g., 10.4.x)
2. Create a table with a CHECK constraint:

CREATE TABLE inventories (
    id INT AUTO_INCREMENT PRIMARY KEY,
    items LONGTEXT,
    CONSTRAINT items CHECK (json_valid(items))
);

3. Run npx drizzle-kit push
4. Observe: exits with code 1 during schema pull

Fixes #5550