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💻 Software🗄️ Databases

Migration generate drops/creates all constraints

Fresh3 days ago
Mar 14, 20260 views
Confidence Score72%
72%

Problem

Issue type: [ ] question [x ] bug report [ ] feature request [ ] documentation issue Database system/driver: [ ] `cordova` [ ] `mongodb` [ ] `mssql` [ ] `mysql` / `mariadb` [ ] `oracle` [x] `postgres` [ ] `sqlite` [ ] `sqljs` [ ] `websql` TypeORM version: [ ] `latest` [x] `@next` [ ] `0.x.x` (or put your version here) On an existing database in PostgreSQL 9.6.2 migration generation wants to drop all unique constraints and create them again. I ran this migration however it wants to do it on the next generate as well. The only thing I can tell(without digging into the code) is that the order in [code block] is backwards on the columns in the SQL statement..

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1 Fix

Canonical Fix
Unverified Fix
New Fix – Awaiting Verification

Fix Migration Generation for Unique Constraints in PostgreSQL

Medium Risk

The migration generation process in TypeORM for PostgreSQL is incorrectly identifying the order of columns in unique constraints, leading to unnecessary drops and recreations of these constraints. This behavior is likely due to a mismatch between the expected column order in the database schema and how TypeORM interprets it during migration generation.

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  1. 1

    Review Existing Unique Constraints

    Examine the current unique constraints in your PostgreSQL database to verify their column order. This can be done by querying the information schema.

    sql
    SELECT * FROM information_schema.table_constraints WHERE constraint_type = 'UNIQUE';
  2. 2

    Update Entity Definitions

    Ensure that the entity definitions in your TypeORM models match the column order of the unique constraints in the database. Adjust the order in your entity classes accordingly.

    typescript
    export class YourEntity {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  columnA: string;

  @Column()
  columnB: string;

  @Unique(['columnA', 'columnB'])
  @Column()
  columnC: string;
}
  3. 3

    Regenerate Migrations

    After updating the entity definitions, regenerate the migrations to ensure TypeORM correctly identifies the constraints without dropping them unnecessarily.

    bash
    typeorm migration:generate -n UpdateUniqueConstraints
  4. 4

    Apply Migrations

    Run the newly generated migrations to apply the changes to your database. This will ensure that the unique constraints are correctly set without unnecessary drops.

    bash
    typeorm migration:run
  5. 5

    Test Migration Generation

    After applying the migrations, run the migration generation command again to confirm that TypeORM no longer attempts to drop and recreate the unique constraints.

    bash
    typeorm migration:generate -n TestMigrationGeneration

Validation

To confirm the fix worked, check the output of the migration generation command. It should not list any unique constraints as needing to be dropped or recreated. Additionally, verify the unique constraints in the database to ensure they are intact.

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Environment

Submitted by

AC

Alex Chen

2450 rep

Tags

typeormormtypescriptcomp:-migrations