MySQL Engineering
Acknowledgement: Shared by Peter Bamuhigire, techguypeter.com, +256 784 464178.
Use this parent skill as the active MySQL engineering entrypoint. It keeps routing narrow while preserving the older MySQL child skills as reference modules.
Use When
- Designing MySQL-backed features, schemas, migrations, indexes, keys, and query paths.
- Reviewing MySQL SQL correctness, transaction behaviour, locking assumptions, or data modelling choices.
- Implementing stored routines, generated columns, JSON usage, or application data-access conventions.
Do Not Use When
- The task is unrelated to this parent skill or is better handled by a narrower active parent named in the workflow.
- The request only needs a trivial answer and no reference module needs to be loaded.
Required Inputs
- Gather the concrete system, repository, environment, constraints, and deliverable before loading references.
- Identify which absorbed reference file is needed; do not load every migrated reference by default.
Workflow
- Start with
database-design-engineeringfor model, integrity, tenancy, migration, and access-pattern framing. - Load only the needed reference:
references/mysql-best-practices.mdfor MySQL defaults, constraints, engine choices, and safe conventions.references/mysql-data-modeling.mdfor schema and relationship design.references/mysql-advanced-sql.mdfor advanced query and SQL patterns.
- Administration, performance, backup, restore, and incident work also route here (the retired
mysql-operationsskill is an inactive alias of this skill).
Quality Standards
- Make storage engine, character set, collation, key, and transaction assumptions explicit.
- Prefer integrity in schema constraints and transactional boundaries before application-only enforcement.
- Include migration safety notes for locks, long-running changes, rollback, and data verification.
Anti-Patterns
- Treating absorbed reference files as active skills or separate routing entrypoints.
- Loading every migrated child reference instead of the one that matches the task.
- Producing generic advice without constraints, evidence, or next verification steps.
Outputs
- MySQL schema, SQL, migration, or review output with loaded references and validation evidence.
References
- Load the retained MySQL operations workflow for backup, restore, replication, production tuning, monitoring, and incidents.
- Load only the references/.md files named in the workflow when their depth is required.
Evidence Produced
| Category | Artifact | Format | Example |
|---|---|---|---|
| Data safety | MySQL schema and operations evidence pack | DDL, query plans, and runbook | constraints, migration, backup/restore, performance capture, and rollback |
Inputs
| Input | Required | Purpose |
|---|---|---|
| MySQL version and schema | yes | Select valid features |
| Query shapes and cardinalities | yes | Design indexes |
| Migration and availability constraints | yes | Plan safe change |
Capability contract
Review SQL and propose DDL by default. Execute migrations, routines, or data changes only with authorised credentials, environment scope, backup evidence, and rollback.
Degraded mode
If EXPLAIN plans or production statistics are unavailable, provide read-only hypotheses and validation SQL; do not claim a query is tuned.
Decision rules
| Condition | Action |
|---|---|
| Scan is selective and frequent | Evaluate a covering index |
| DDL may lock a hot table | Use an online or staged migration |
| Constraint encodes business truth | Enforce it in the database |
Domain Anti-Patterns
- Using SELECT star in stable contracts. Fix: name columns.
- Building SQL by interpolation. Fix: bind parameters.
- Adding indexes without write-cost review. Fix: measure both paths.
- Using zero dates as missing values. Fix: use nullable semantics.
- Changing a hot table without lock analysis. Fix: test the DDL plan.
