Repository navigation
feat: Add Declarative Schema DSL and Reversible Migrations - #4
Merged
Merged
Conversation
Schema is a value you can diff. Up is desired minus current, down is the reverse diff so drops still recreate tables. The runner journals zero-padded ids and refuses holes in the applied prefix.
SQLite rejects DROP COLUMN while an index still references the column. Postgres would drop the index with the column and then fail the extra DROP INDEX. Emit those index drops first, and only once. SQLite also cannot DROP COLUMN for PRIMARY KEY, UNIQUE, or foreign keys, or ADD COLUMN NOT NULL without DEFAULT. Fail at compile time instead of emitting data-dependent DDL.
SQLite and Postgres both require the referenced column to be a primary key, UNIQUE, or covered by a single-column unique index. defineSchema now throws at schema time instead of letting CREATE TABLE succeed and INSERT fail with a foreign key mismatch.
SQLite refuses ADD COLUMN with a REFERENCES clause and a non-NULL default, and it refuses CURRENT_TIME/DATE/TIMESTAMP or parenthesized defaults. Fail those in compileOps before apply. CREATE TABLE with the same column, and constant defaults on ADD COLUMN, still compile.
SQLite treats DEFAULT NULL the same as a missing default on ADD COLUMN NOT NULL. Fail those in compileOps. CREATE TABLE with the same column still compiles and applies.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Schema is a value now: tables, columns, indexes, and foreign keys. diffSchema walks two schemas and emits create/drop/add ops in foreign-key order. Indexes that reference a removed column are dropped before the column, and only once. The down path is the same function with the arguments swapped, so a drop still knows how to recreate the table.
The runner records zero-padded ids in _schema_migrations, refuses holes in the applied prefix, and wraps each step in a transaction. Changing a column in place throws. SQLite refuses UNIQUE or PRIMARY KEY on ADD COLUMN, DROP COLUMN on UNIQUE, PRIMARY KEY, or foreign-key columns, ADD COLUMN NOT NULL without a non-NULL DEFAULT, ADD COLUMN REFERENCES with a non-NULL default, and ADD COLUMN with CURRENT_TIME/DATE/TIMESTAMP or a parenthesized default. Those need a table rebuild, a unique index, or a nullable FK with no default. CREATE TABLE still accepts a non-NULL FK default and a NOT NULL DEFAULT NULL column. defineSchema also refuses a foreign key unless the parent column is a primary key, UNIQUE, or the single column of a unique index, so sqlite cannot CREATE TABLE then fail INSERT with a foreign key mismatch. Live apply is sqlite; postgres is compileOps string checks plus journal placeholders.
Closes #3