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Writing a migration

All column names will be translated to snake_case if snakeCase option is set to true in rakeDb options.

Use a change function for changing the database schema, it accepts a callback with db and optionally you can use a second argument up to know if it is an up migration or down.

ts
import { change } from '../dbScript';

change(async (db, up) => {
  if (up) {
    console.log('migrate is called');
  } else {
    console.log('rollback is called');
  }
});

A single migration file can have multiple changes.

It's useful when creating a database schema or enum, and then creating a table that depends on it.

When migrating, changes are executed from top to bottom, so the schema and the enum will be created before the table.

On rollback, changes are executed from bottom to top, so the schema and the enum will be dropped after the table that is using them.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createSchema('custom');
  await db.createEnum('yearSeason', ['spring', 'summer', 'fall', 'winter']);
});

change(async (db) => {
  await db.createTable('custom.table', (t) => ({
    id: t.identity().primaryKey(),
    season: t.enum('yearSeason'),
  }));
});

db is an extended query builder, so it has all the same methods as a query builder and additional specific methods such as createTable, changeTable, and others.

Example of creating a table and populating it with values:

ts
import { change } from '../src';

change(async (db, up) => {
  const { table } = await db.createTable('languages', (t) => ({
    id: t.identity().primaryKey(),
    // `string` is a varchar with a limit 255 by default.
    name: t.string().unique(),
    code: t.string().unique(),
  }));

  // it's important to use this `up` check to not run the queries on rollback
  if (up) {
    // TS knows the column types, so this will be type-checked:
    await table.createMany([
      { name: 'Ukrainian', code: 'ua' },
      { name: 'English', code: 'en' },
      { name: 'Polish', code: 'pl' },
      { name: 'Belarusian', code: 'be' },
      { name: 'French', code: 'fr' },
    ]);

    // use db.query to perform raw SQL queries
    const language = 'Ukrainian';
    const { rows } = await db.query`
      SELECT * FROM languages WHERE name = ${language}
    `;
    console.log(rows);
  }
});

default export

In some setups it may be required to load multiple migrations first, and execute them later.

The problem is, rakeDb wouldn't know which db changes belong to which migration files, and you need to do default exports to solve it:

ts
import { change } from '../src';

export default change(async (db, up) => {
  const { table } = await db.createTable('table', (t) => ({
    // ...
  }));
});

If there are multiple changes in the same file, export default an array:

ts
import { change } from '../src';

export default [
  change(async (db, up) => {
    // change 1
  }),
  change(async (db, up) => {
    // change 2
  }),
];

To accidentally not forgot to write a default export, set forceDefaultExports to true in a rakeDb config.

createTable, dropTable

createTable accepts a string for a table name, optional options, and a callback to specify columns.

dropTable accepts the same arguments, it will drop the table when migrating and create a table when rolling back.

To create an empty table, the callback with columns may be omitted.

When creating a table within a specific schema, write the table name with schema name: 'schemaName.tableName'.

Returns object { table: TableInterface } that allows to insert records right after creating a table.

Options are:

ts
type TableOptions = {
  // create the table only if it not exists already
  createIfNotExists?: boolean;

  // drop the table only if it exists
  dropIfExists?: boolean;

  // used when reverting a `createTable`
  dropMode?: 'CASCADE' | 'RESTRICT';

  // add a database comment on the table
  comment?: string;

  // by default, it will throw an error when the table has no primary key
  // set `noPrimaryKey` to `true` to bypass it
  noPrimaryKey?: boolean;

  // override rakeDb `snakeCase` option for only this table
  snakeCase?: boolean;
};

Example:

ts
import { change } from '../dbScript';

change(async (db, up) => {
  // call `createTable` with options
  await db.createTable(
    'table',
    {
      comment: 'Table comment',
      dropMode: 'CASCADE',
      noPrimaryKey: true,
    },
    (t) => ({
      // ...
    }),
  );

  // call without options
  const { table } = await db.createTable('user', (t) => ({
    id: t.identity().primaryKey(),
    email: t.text().unique(),
    name: t.text(),
    active: t.boolean().nullable(),
    ...t.timestamps(),
  }));

  // create records only when migrating up
  if (up) {
    // table is a db table interface, all query methods are available
    await table.createMany([...data]);
  }
});

changeTable

changeTable accepts a table name, optional options, and a special callback with column changes.

When changing a table within a specific schema, write the table name with schema name: 'schemaName.tableName'.

Options are:

ts
type ChangeTableOptions = {
  comment?:
    | // add a comment to the table on migrating, remove a comment on rollback
    string // change comment from first to second on migrating, from second to first on rollback
    | [string, string] // remove a comment on both migrate and rollback
    | null;

  // override rakeDb `snakeCase` option for only this table
  snakeCase?: boolean;
};

The callback of the changeTable is different from createTable in the way that it expects columns to be wrapped in change methods such as add, drop, and change.

add, drop

add will add a column (or a check) on migrating, and remove it on rollback.

drop will remove a column (or a check) on migrating, and add it on rollback.

The column in add or drop can have all the same methods as when creating a table, such methods as index, unique, and foreignKey.

Supports adding a composite primary key, foreign key, and index, and all the same as when creating a table.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeTable('table', (t) => ({
    // add column
    column1: t.add(t.text()),

    // remove column
    column2: t.drop(t.boolean()),

    // add a check to the column
    column3: t.add(t.check(t.sql`column3 > 5`)),

    // remove a check from the column
    column4: t.drop(t.check(t.sql`column4 > 5`)),

    // add composite primary key:
    ...t.add(t.primaryKey(['foo', 'bar'])),

    // add composite index:
    ...t.add(t.index(['foo', 'bar'])),

    // add composite unique index:
    ...t.add(t.unique(['foo', 'bar'])),

    // add composite foreign key:
    ...t.add(
      t.foreignKey(['foo', 'bar'], 'otherTable', ['otherFoo', 'otherBar']),
    ),

    // add a table check
    ...t.add(t.check(t.sql`column3 > column4`)),

    // add a constraint
    ...t.add(
      t.constraint({
        name: 'constraintName',
        check: t.sql`column3 < 20`,
        foreignKey: [['foo', 'bar'], 'otherTable', ['otherFoo', 'otherBar']],
      }),
    ),

    // add timestamps:
    ...t.add(t.timestamps()),
  }));
});

t.add in changeTable may be omitted:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeTable('table', (t) => ({
    // add column when migrating up, drop it when mirating down
    column: t.text(),
  }));
});

change

Takes an array of two columns (or checks). When migrating, it will change the column to the second element, and when doing rollback will change the column to the first element.

Dropping or creating a primary key on multiple columns is allowed.

Index options are listed here.

Foreign key options are listed here.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeTable('table', (t) => ({
    // change column type from integer to varchar(255)
    column1: t.change(t.integer(), t.string()),

    // change column type using SQL expression to convert data
    column2: t.change(t.integer(), t.string(), {
      usingUp: t.sql`column2::text`,
      usingDown: t.sql`column2::integer`,
    }),

    // change column default
    column3: t.change(t.default(1), t.default(2)),

    // it's important to specify a column type (json)
    // when we want the value to be correctly serialized:
    // t.json().default([]) will be serialized with JSON.stringify,
    // t.default([]) won't.
    column4: t.change(t.json(), t.json().default([])),

    // change column default with raw SQL
    column5: t.change(t.default(t.sql`2 + 2`), t.default(t.sql`3 + 3`)),

    // change column to be nullable or non-nullable
    column6: t.change(t.nonNullable(), t.nullable()),
    column7: t.change(t.nullable(), t.nonNullable()),

    // change column comment
    column8: t.change(t.comment('from comment'), t.comment('to comment')),

    // add index
    column9: t.change(t.integer(), t.integer().index()),

    // remove index
    column10: t.change(t.integer().index(), t.integer()),

    // change index
    column11: t.change(
      t.integer().index({
        // index options to be applied when migrating down
      }),
      t.integer().index({
        // index options to be applied when migrating up
      }),
    ),

    // add primary key
    column12: t.change(t.integer(), t.integer().primaryKey()),

    // drop primary key
    column13: t.change(t.integer().primaryKey(), t.integer()),

    // add foreign key
    column14: t.change(
      t.integer(),
      t.integer().foreignKey('otherTable', 'otherTableId'),
    ),

    // remove foreign key
    column15: t.change(
      t.integer().foreignKey('otherTable', 'otherTableId'),
      t.integer(),
    ),

    // change foreign key
    column16: t.change(
      t.integer().foreignKey('oneTable', 'oneColumn', {
        // foreign key options to be applied when migrating up
        name: 'oneForeignKeyName',
        match: 'PARTIAL',
        onUpdate: 'RESTRICT',
        onDelete: 'SET DEFAULT',
      }),
      t.integer().foreignKey('otherTable', 'otherColumn', {
        // foreign key options to be applied when migrating down
        name: 'otherForeignKeyName',
        match: 'FULL',
        onUpdate: 'NO ACTION',
        onDelete: 'CASCADE',
      }),
    ),

    // change various column properties at once
    column17: t.change(
      t
        .integer()
        .collate('de_DE')
        .default(123)
        .comprssion('pglz')
        .comment('from comment')
        .index({ name: 'oneIndexName' })
        .foreignKey('oneTable', 'oneColumn', {
          name: 'oneForeignKeyName',
        }),
      t
        .text()
        .collate('es_ES')
        .default('123')
        .compression('lz4')
        .comment('to comment')
        .nullable()
        .index({ name: 'otherIndexName' })
        .foreignKey('otherTable', 'otherColumn', {
          name: 'otherForeignKeyName',
        }),
    ),

    column18: t.change(
      // change from this check:
      t.check(t.sql`column17 > 5`),
      // to this check:
      t.check(t.sql`column17 < 10`),
    ),
  }));
});

rename

Rename a column:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeTable('table', (t) => ({
    oldColumnName: t.rename('newColumnName'),
  }));
});

renameTable

Rename a table:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameTable('oldTableName', 'newTableName');
});

Prefix table name with a schema to set a different schema:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameTable('fromSchema.oldTable', 'toSchema.newTable');
});

changeTableSchema

Set a different schema to the table:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeTableSchema('tableName', 'fromSchema', 'toSchema');
});

addColumn, dropColumn

Add a column to the table on migrating, and remove it on rollback.

dropColumn takes the same arguments, removes a column on migrate, and adds it on rollback.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.addColumn('tableName', 'columnName', (t) =>
    t.integer().index().nullable(),
  );
});

addIndex, dropIndex

Add an index to the table on migrating, and remove it on rollback.

dropIndex takes the same arguments, removes the index on migrate, and adds it on rollback.

The first argument is the table name, other arguments are the same as in composite index.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.addIndex(
    'tableName',
    ['column1', { column: 'column2', order: 'DESC' }],
    {
      name: 'indexName',
    },
  );
});

renameIndex

Rename index:

ts
import { change } from '../dbScript';

change(async (db) => {
  // tableName can be prefixed with a schema
  await db.renameIndex('tableName', 'oldIndexName', 'newIndexName');
});

addForeignKey, dropForeignKey

Add a foreign key to a table on migrating, and remove it on rollback.

dropForeignKey takes the same arguments, removes the foreign key on migrate, and adds it on rollback.

Arguments:

  • table name
  • column names in the table
  • other table name
  • column names in the other table
  • options:
    • name: constraint name
    • match: 'FULL', 'PARTIAL', or 'SIMPLE'
    • onUpdate and onDelete: 'NO ACTION', 'RESTRICT', 'CASCADE', 'SET NULL', or 'SET DEFAULT'

The first argument is the table name, other arguments are the same as in composite foreign key.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.addForeignKey(
    'tableName',
    ['id', 'name'],
    'otherTable',
    ['foreignId', 'foreignName'],
    {
      name: 'constraintName',
      match: 'FULL',
      onUpdate: 'RESTRICT',
      onDelete: 'CASCADE',
    },
  );
});

addPrimaryKey, dropPrimaryKey

Add a primary key to a table on migrate, and remove it on rollback.

dropPrimaryKey takes the same arguments, removes the primary key on migrate, and adds it on rollback.

First argument is a table name, second argument is an array of columns. The optional third argument may have a name for the primary key constraint.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.addPrimaryKey('tableName', ['id', 'name'], {
    name: 'tablePkeyName',
  });
});

addCheck, dropCheck

Add or drop a check for multiple columns.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.addCheck('tableName', t.sql`column > 123`);
});

renameConstraint

Rename a table constraint such as a primary key or a database check

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameConstraint(
    'tableName', // may include schema: 'schema.table'
    'oldConstraintName',
    'newConstraintName',
  );
});

renameColumn

Rename a column:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameColumn('tableName', 'oldColumnName', 'newColumnName');
});

createEnum, dropEnum

createEnum creates an enum on migrate, drops it on rollback.

dropEnum does the opposite.

Third argument for options is optional.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createEnum('numbers', ['one', 'two', 'three']);

  // use `schemaName.enumName` format to specify a schema
  await db.createEnum('customSchema.mood', ['sad', 'ok', 'happy'], {
    // following options are used when dropping enum
    dropIfExists: true,
    cascade: true,
  });
});

addEnumValues, dropEnumValues

Use these methods to add or drop one or multiple values from an existing enum.

addEnumValues will drop values when rolling back the migration.

Dropping a value internally acts in multiple steps:

  1. Select all columns from the database that depends on the enum;
  2. Alter all these columns to have text type;
  3. Drop the enum;
  4. Re-create the enum without the value given;
  5. Alter all columns from the first step to have the enum type;

In the case when the value is used by some table, migrating dropEnumValue or rolling back addEnumValue will throw an error with a descriptive message, in such case you'd need to manually resolve the issue by deleting rows with the value, or changing such values.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.addEnumValue('numbers', 'four');

  // you can pass options
  await db.addEnumValue('numbers', 'three', {
    // where to insert
    before: 'four',
    // skip if already exists
    ifNotExists: true,
  });

  // enum name can be prefixed with schema
  await db.addEnumValue('public.numbers', 'five', {
    after: 'four',
  });
});

changeEnumValues

Drops the enum and re-creates it with a new set of values. Before dropping, changes all related column types to text, and after creating changes types back to the enum, in the same way as dropEnumValues works.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeEnumValues(
    // can be prefixed with schema: 'public.numbers'
    'numbers',
    // change from:
    ['one', 'two'],
    // change to:
    ['three', 'four'],
  );
});

renameEnumValues

Rename one or multiple enum values using this method:

ts
import { change } from '../dbScript';

change(async (db) => {
  // rename value "from" to "to"
  await db.rename('numbers', { from: 'to' });

  // enum name can be prefixed with schema
  await db.rename('public.numbers', { from: 'to' });
});

renameType

Rename a type (such as enum):

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameType('oldTypeName', 'newTypeName');
});

Prefix the type name with a schema to set a different schema:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameType('fromSchema.oldType', 'toSchema.newType');
});

changeTypeSchema

Set a different schema to the type (such as enum):

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.changeTypeSchema('typeName', 'fromSchema', 'toSchema');
});

createSchema, dropSchema

createSchema creates a database schema, and removes it on rollback.

dropSchema takes the same arguments, removes schema on migration, and adds it on rollback.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createSchema('schemaName');
});

renameSchema

Renames a database schema, renames it backwards on roll back.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameSchema('from', 'to');
});

createExtension, dropExtension

createExtension creates a database extension, and removes it on rollback.

dropExtension takes the same arguments, removes the extension on migrate, and adds it on rollback.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createExtension('pg_trgm');
});

createDomain, dropDomain

Domain is a custom database type that is based on other type and can include NOT NULL and a CHECK (see postgres tutorial).

Construct a column type in the function as the second argument.

Specifiers nullable, default, check, collate will be saved to the domain type on database level.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createDomain('domainName', (t) =>
    t.integer().check(t.sql`value = 42`),
  );

  // use `schemaName.domainName` format to specify a schema
  await db.createDomain('schemaName.domainName', (t) =>
    t
      .text()
      .nullable()
      .collate('C')
      .default('default text')
      .check(t.sql`length(value) > 10`),
  );
});

renameDomain

To rename a domain:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.renameDomain('oldName', 'newName');

  // to move domain to a different schema
  await db.renameDomain('oldSchema.domain', 'newSchema.domain');
});

createCollation, dropCollation

Create and drop a database collation, (see Postgres docs).

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createCollation('myCollation', {
    // This is a shortcut for setting lcCollate and lcCType at once.
    locale: 'en-u-kn-true',

    // set `lcType` and `lcCType` only if the `locale` is not set.
    // lcType: 'C',
    // lcCType: 'C',

    // provider can be 'icu' or 'libc'. 'libc' is a default.
    provider: 'icu',

    // true by default, false is only supported with 'icu' provider.
    deterministic: true,

    // Is intended to by used by `pg_upgrade`. Normally, it should be omitted.
    version: '1.2.3',

    // For `CREATE IF NOT EXISTS` when creating.
    createIfNotExists: true,

    // For `DROP IF EXISTS` when dropping.
    dropIfExists: true,

    // For `DROP ... CASCADE` when dropping.
    cascase: true,
  });
});

Instead of specifying the collation options, you can specify a collation to copy options from.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createCollation('myCollation', {
    fromExisting: 'otherCollation',
  });
});

To create a collation withing a specific database schema, prepend it to the collation name:

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createCollation('schemaName.myCollation', {
    // `fromExisting` also can accept a collation name with a schema.
    fromExisting: 'schemaName.otherCollation',
  });
});

createView, dropView

Create and drop database views.

Provide SQL as a string or via t.sql that can accept variables.

ts
import { change } from '../dbScript';

change(async (db) => {
  await db.createView(
    'simpleView',
    `
    SELECT a.one, b.two
    FROM a
    JOIN b ON b."aId" = a.id
  `,
  );

  // view can accept t.sql with variables in such way:
  const value = 'some value';
  await db.createView(
    'viewWithVariables',
    t.sql`
      SELECT * FROM a WHERE key = ${value}
    `,
  );

  // view with options
  await db.createView(
    'schemaName.recursiveView',
    {
      // createOrReplace has effect when creating the view
      createOrReplace: true,

      // dropIfExists and dropMode have effect when dropping the view
      dropIfExists: true,
      dropMode: 'CASCADE',

      // for details, check Postgres docs for CREATE VIEW,
      // these options are matching CREATE VIEW options
      temporary: true,
      recursive: true,
      columns: ['n'],
      with: {
        checkOption: 'LOCAL', // or 'CASCADED'
        securityBarrier: true,
        securityInvoker: true,
      },
    },
    `
      VALUES (1)
      UNION ALL
      SELECT n + 1 FROM "schemaName"."recursiveView" WHERE n < 100;
    `,
  );
});

tableExists

Returns boolean to know if table exists:

ts
import { change } from '../dbScript';

change(async (db) => {
  if (await db.tableExists('tableName')) {
    // ...do something
  }
});

columnExists

Returns boolean to know if a column exists:

Note that when snakeCase option is set to true, this method won't translate column to snake case, unlike other parts.

ts
import { change } from '../dbScript';

change(async (db) => {
  if (await db.columnExists('tableName', 'columnName')) {
    // ...do something
  }
});

constraintExists

Returns boolean to know if constraint exists:

ts
import { change } from '../dbScript';

change(async (db) => {
  if (await db.constraintExists('constraintName')) {
    // ...do something
  }
});