Database Migration Agent Skill

Execute database migrations across ORMs and platforms with zero-downtime strategies, data transformation, and rollback procedures. Use when migrating databases, changing schemas, performing data transformations, or implementing zero-downtime deployment strategies.

2k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

38452

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/wshobson/agents --skill database-migration

The instruction itself

16 sections, as written by the author

Database Migration

Master database schema and data migrations across ORMs (Sequelize, TypeORM, Prisma), including rollback strategies and zero-downtime deployments.

When to Use This Skill

Migrating between different ORMs
Performing schema transformations
Moving data between databases
Implementing rollback procedures
Zero-downtime deployments
Database version upgrades
Data model refactoring

ORM Migrations

Sequelize Migrations

// migrations/20231201-create-users.js
module.exports = {
  up: async (queryInterface, Sequelize) => {
    await queryInterface.createTable("users", {
      id: {
        type: Sequelize.INTEGER,
        primaryKey: true,
        autoIncrement: true,
      },
      email: {
        type: Sequelize.STRING,
        unique: true,
        allowNull: false,
      },
      createdAt: Sequelize.DATE,
      updatedAt: Sequelize.DATE,
    });
  },

  down: async (queryInterface, Sequelize) => {
    await queryInterface.dropTable("users");
  },
};

// Run: npx sequelize-cli db:migrate
// Rollback: npx sequelize-cli db:migrate:undo

TypeORM Migrations

// migrations/1701234567-CreateUsers.ts
import { MigrationInterface, QueryRunner, Table } from "typeorm";

export class CreateUsers1701234567 implements MigrationInterface {
  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.createTable(
      new Table({
        name: "users",
        columns: [
          {
            name: "id",
            type: "int",
            isPrimary: true,
            isGenerated: true,
            generationStrategy: "increment",
          },
          {
            name: "email",
            type: "varchar",
            isUnique: true,
          },
          {
            name: "created_at",
            type: "timestamp",
            default: "CURRENT_TIMESTAMP",
          },
        ],
      }),
    );
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.dropTable("users");
  }
}

// Run: npm run typeorm migration:run
// Rollback: npm run typeorm migration:revert

Prisma Migrations

// schema.prisma
model User {
  id        Int      @id @default(autoincrement())
  email     String   @unique
  createdAt DateTime @default(now())
}

// Generate migration: npx prisma migrate dev --name create_users
// Apply: npx prisma migrate deploy

Schema Transformations

Adding Columns with Defaults

// Safe migration: add column with default
module.exports = {
  up: async (queryInterface, Sequelize) => {
    await queryInterface.addColumn("users", "status", {
      type: Sequelize.STRING,
      defaultValue: "active",
      allowNull: false,
    });
  },

  down: async (queryInterface) => {
    await queryInterface.removeColumn("users", "status");
  },
};

Renaming Columns (Zero Downtime)

// Step 1: Add new column
module.exports = {
  up: async (queryInterface, Sequelize) => {
    await queryInterface.addColumn("users", "full_name", {
      type: Sequelize.STRING,
    });

    // Copy data from old column
    await queryInterface.sequelize.query("UPDATE users SET full_name = name");
  },

  down: async (queryInterface) => {
    await queryInterface.removeColumn("users", "full_name");
  },
};

// Step 2: Update application to use new column

// Step 3: Remove old column
module.exports = {
  up: async (queryInterface) => {
    await queryInterface.removeColumn("users", "name");
  },

  down: async (queryInterface, Sequelize) => {
    await queryInterface.addColumn("users", "name", {
      type: Sequelize.STRING,
    });
  },
};

Changing Column Types

module.exports = {
  up: async (queryInterface, Sequelize) => {
    // For large tables, use multi-step approach

    // 1. Add new column
    await queryInterface.addColumn("users", "age_new", {
      type: Sequelize.INTEGER,
    });

    // 2. Copy and transform data
    await queryInterface.sequelize.query(`
      UPDATE users
      SET age_new = CAST(age AS INTEGER)
      WHERE age IS NOT NULL
    `);

    // 3. Drop old column
    await queryInterface.removeColumn("users", "age");

    // 4. Rename new column
    await queryInterface.renameColumn("users", "age_new", "age");
  },

  down: async (queryInterface, Sequelize) => {
    await queryInterface.changeColumn("users", "age", {
      type: Sequelize.STRING,
    });
  },
};

Data Transformations

Complex Data Migration

module.exports = {
  up: async (queryInterface, Sequelize) => {
    // Get all records
    const [users] = await queryInterface.sequelize.query(
      "SELECT id, address_string FROM users",
    );

    // Transform each record
    for (const user of users) {
      const addressParts = user.address_string.split(",");

      await queryInterface.sequelize.query(
        `UPDATE users
         SET street = :street,
             city = :city,
             state = :state
         WHERE id = :id`,
        {
          replacements: {
            id: user.id,
            street: addressParts[0]?.trim(),
            city: addressParts[1]?.trim(),
            state: addressParts[2]?.trim(),
          },
        },
      );
    }

    // Drop old column
    await queryInterface.removeColumn("users", "address_string");
  },

  down: async (queryInterface, Sequelize) => {
    // Reconstruct original column
    await queryInterface.addColumn("users", "address_string", {
      type: Sequelize.STRING,
    });

    await queryInterface.sequelize.query(`
      UPDATE users
      SET address_string = CONCAT(street, ', ', city, ', ', state)
    `);

    await queryInterface.removeColumn("users", "street");
    await queryInterface.removeColumn("users", "city");
    await queryInterface.removeColumn("users", "state");
  },
};

Rollback Strategies

Transaction-Based Migrations

module.exports = {
  up: async (queryInterface, Sequelize) => {
    const transaction = await queryInterface.sequelize.transaction();

    try {
      await queryInterface.addColumn(
        "users",
        "verified",
        { type: Sequelize.BOOLEAN, defaultValue: false },
        { transaction },
      );

      await queryInterface.sequelize.query(
        "UPDATE users SET verified = true WHERE email_verified_at IS NOT NULL",
        { transaction },
      );

      await transaction.commit();
    } catch (error) {
      await transaction.rollback();
      throw error;
    }
  },

  down: async (queryInterface) => {
    await queryInterface.removeColumn("users", "verified");
  },
};

Checkpoint-Based Rollback

module.exports = {
  up: async (queryInterface, Sequelize) => {
    // Create backup table
    await queryInterface.sequelize.query(
      "CREATE TABLE users_backup AS SELECT * FROM users",
    );

    try {
      // Perform migration
      await queryInterface.addColumn("users", "new_field", {
        type: Sequelize.STRING,
      });

      // Verify migration
      const [result] = await queryInterface.sequelize.query(
        "SELECT COUNT(*) as count FROM users WHERE new_field IS NULL",
      );

      if (result[0].count > 0) {
        throw new Error("Migration verification failed");
      }

      // Drop backup
      await queryInterface.dropTable("users_backup");
    } catch (error) {
      // Restore from backup
      await queryInterface.sequelize.query("DROP TABLE users");
      await queryInterface.sequelize.query(
        "CREATE TABLE users AS SELECT * FROM users_backup",
      );
      await queryInterface.dropTable("users_backup");
      throw error;
    }
  },
};

Additional patterns and templates

More detailed templates and worked examples live in references/details.md. Read that file for the full pattern library.

Other skills for the same job

different authors, same section of the catalogue

Biorxiv Database

by christophacham

×4

Efficient database search tool for bioRxiv preprint server. Use this skill when searching for life sciences preprints by keywords, authors, date ranges, or categories, retrieving paper metadata, downloading PDFs, or conducting literature reviews.

Access BRENDA enzyme database via SOAP API. Retrieve kinetic parameters (Km, kcat), reaction equations, organism data, and substrate-specific enzyme information for biochemical research and metabolic pathway analysis.

Access ClinPGx pharmacogenomics data (successor to PharmGKB). Query gene-drug interactions, CPIC guidelines, allele functions, for precision medicine and genotype-guided dosing decisions.

Query NCBI ClinVar for variant clinical significance. Search by gene/position, interpret pathogenicity classifications, access via E-utilities API or FTP, annotate VCFs, for genomic medicine.

Access COSMIC cancer mutation database. Query somatic mutations, Cancer Gene Census, mutational signatures, gene fusions, for cancer research and precision oncology. Requires authentication.

Query Ensembl genome database REST API for 250+ species. Gene lookups, sequence retrieval, variant analysis, comparative genomics, orthologs, VEP predictions, for genomic research.

Query openFDA API for drugs, devices, adverse events, recalls, regulatory submissions (510k, PMA), substance identification (UNII), for FDA regulatory data analysis and safety research.

Query NCBI Gene via E-utilities/Datasets API. Search by symbol/ID, retrieve gene info (RefSeqs, GO, locations, phenotypes), batch lookups, for gene annotation and functional analysis.

13k tokens scripts

How to use it

Copy the folder

Take wshobson/database-migration from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npx. Without those the skill loads but fails at the first command.