MySQL best practices are proven guidelines for writing performant, maintainable, and secure SQL code.
Use proper data types, add indexes on frequently filtered columns, keep transactions short, always back up, and monitor performance with EXPLAIN
and slow query logs.
Select the smallest data type that safely stores the data.Use INT
for identifiers, DECIMAL(10,2)
for money, VARCHAR
with realistic length, and TINYINT(1)
for booleans.
Index columns used in WHERE
, JOIN
, and ORDER BY
clauses.Composite indexes should match the query's left-most columns.
For fast order lookups, create an index on Orders(customer_id, order_date)
.
Retrieve only required columns, use LIMIT for pagination, avoid SELECT *, and run EXPLAIN
to inspect query plans.
Prepared statements reduce parsing overhead and prevent SQL injection.Use parameterized queries in application code and in MySQL with PREPARE
/ EXECUTE
.
Wrap related DML in START TRANSACTION
… COMMIT
to ensure atomic updates and maintain consistency when inserting orders and their items.
Use mysqldump --single-transaction
for logical backups of InnoDB tables and mysqlbinlog
for point-in-time recovery.
Normalize to 3NF, use surrogate primary keys, enforce foreign keys, and prefer snake_case naming.Document schema changes in version control.
Enable slow_query_log
, set a sane long_query_time
, review plans with EXPLAIN ANALYZE
, and use information_schema
tables for index statistics.
.
No. Create composite indexes only when the query filter order matches the index’s left-most columns and the selectivity justifies it.
No. Prefer InnoDB for nearly all workloads because it offers transactions, row-level locking, crash recovery, and better concurrency.
Run it after large data changes or on a schedule (e.g., weekly) so the optimizer has up-to-date statistics.