Declarative schema management for MySQL. Write the desired schema as plain SQL (CREATE TABLE / CREATE VIEW / etc.); myschema reads the current state from information_schema, diffs the two, and emits — or applies — the DDL that brings current → desired.

export MYSCHEMA_DSN='root@tcp(127.0.0.1:3306)/app'

myschema dump > desired.sql  # capture current schema
vi desired.sql               # describe the schema you want
myschema plan desired.sql    # preview the DDL
myschema apply desired.sql   # run it

The dump → edit → plan → apply → re-plan empty round-trip is the core workflow. See getting-started.md for a ten-minute walkthrough.

brew install winebarrel/myschema/myschema

Download the latest binary from Releases.

Usage: myschema --dsn=STRING <command> [flags]

Flags:
  -h, --help               Show context-sensitive help.
  -d, --dsn=STRING         MySQL DSN including database name (e.g. root@tcp(127.0.0.1:3306)/mydb). See
                           https://github.com/go-sql-driver/mysql#dsn-data-source-name ($MYSCHEMA_DSN)
      --password=STRING    MySQL password (overrides DSN) ($MYSCHEMA_PASSWORD).
      --version

Commands:
  apply --dsn=STRING <files> ... [flags]
    Apply schema changes to the database.

  plan --dsn=STRING <files> ... [flags]
    Print the schema diff SQL without applying it.

  dump --dsn=STRING [flags]
    Dump the current database schema as SQL.

Run "myschema <command> --help" for more information on a command.

myschema dump > current.sql                          # full database
myschema dump --include 'user*' --exclude 'tmp_*'    # filter tables and views
myschema dump --split=./schema/                      # one SQL file per table/view

dump round-trips with plan reporting no changes — the output is the canonical desired-side shape.

myschema plan desired.sql                            # current → desired diff
myschema plan --allow-drop=column,index desired.sql  # allow specific drops
myschema plan --alter-algorithm=INPLACE --alter-lock=NONE desired.sql
myschema plan --bulk-alter desired.sql               # fold same-table ALTERs

Read-only; safe to run repeatedly. Drops blocked by the policy appear as -- skipped: lines so nothing's hidden.

myschema apply desired.sql                           # safe ops only
myschema apply --allow-drop=all desired.sql          # destructive ops too
myschema apply --pre-sql 'SET FOREIGN_KEY_CHECKS=0;' desired.sql

apply runs whatever plan would print, in the same order. Use plan first; apply has no separate confirmation prompt.

• Tables, columns (incl. INVISIBLE on MySQL 8+), primary / unique / check constraints, foreign keys, secondary indexes (with prefix length, DESC, INVISIBLE), generated columns, partitions (RANGE / LIST / HASH / KEY).
• Views (CREATE OR REPLACE on apply; cross-view dependency ordering).
• --include / --exclude glob filtering on table and view names.
• --allow-drop=table,view,column,constraint,foreign_key,index,partition — destructive ops are opt-in, per category. all enables every category at once.
• --alter-algorithm=… / --alter-lock=… — inject MySQL online-DDL hints into every generated ALTER TABLE / CREATE INDEX.
• --bulk-alter — fold consecutive same-table ALTER TABLE statements into one multi-spec ALTER.
• --pre-sql / --pre-sql-file — run session-level SQL on the connection before the diff (e.g. SET FOREIGN_KEY_CHECKS=0).
• --split=<dir> (dump only) — write one SQL file per table / view.
• Directives in desired SQL: -- myschema:renamed-from, -- myschema:convert-charset, -- myschema:execute.

Most flags have a matching MYSCHEMA_* env var (--split is CLI-only).

• MySQL 8+. The catalog reader uses information_schema.CHECK_CONSTRAINTS, STATISTICS.IS_VISIBLE, and emits ALTER TABLE … RENAME COLUMN. MySQL 5.7 isn't supported.
• Go 1.26+ to build from source.

• getting-started.md — install, first DSN, dump → plan → apply round-trip, common flags, directives.
• AGENTS.md — developer guide: feature surface, parser quirks, diff invariants, layout. Read before sending a PR.
• CAVEATS.md — operational rules, sharp edges, what myschema deliberately doesn't manage (triggers, routines, events, sequences).
• PARTITIONING.md — partition-diff scope and limits.

• pistachio — declarative schema management for PostgreSQL.
• ridgepole — DB schema management using a Rails DSL.