knex-schema-inspector
Utility for extracting information about existing DB schema
This library currently supports Postgres, MySQL, MS SQL, SQLite, and OracleDB. We aim to have support for the same databases as the main knex project.
Installation
Install the package through NPM or Yarn:
npm install knex-schema-inspector
yarn add knex-schema-inspector
Usage
The package is initialized by passing it an instance of Knex:
import Knex from 'knex';
import schemaInspector from 'knex-schema-inspector';
const database = Knex({
client: 'mysql',
connection: {
host: '127.0.0.1',
user: 'your_database_user',
password: 'your_database_password',
database: 'myapp_test',
charset: 'utf8',
},
});
const inspector = schemaInspector(database);
export default inspector;
Examples
import inspector from './inspector';
async function logTables() {
const tables = await inspector.tables();
console.log(tables);
}
API
Note: MySQL doesn't support the schema
parameter, as schema and database are ambiguous in MySQL.
Note 2: Some database types might return slightly more information than others. See the type files for a specific overview what to expect from driver to driver.
Note 3: MSSQL doesn't support comment for either tables or columns
Methods
Table
Columns
Foreign Keys
Misc.
Tables
tables(): Promise<string[]>
Retrieve all tables in the current database.
await inspector.tables();
// => ['articles', 'images', 'reviews']
tableInfo(table?: string): Promise<Table | Table[]>
Retrieve the table info for the given table, or all tables if no table is specified
await inspector.tableInfo('articles');
// => {
// name: 'articles',
// schema: 'project',
// comment: 'Informational blog posts'
// }
await inspector.tableInfo();
// => [
// {
// name: 'articles',
// schema: 'project',
// comment: 'Informational blog posts'
// },
// { ... },
// { ... }
// ]
hasTable(table: string): Promise<boolean>
Check if a table exists in the current database.
await inspector.hasTable('articles');
// => true
Columns
columns(table?: string): Promise<{ table: string, column: string }[]>
Retrieve all columns in a given table, or all columns if no table is specified
await inspector.columns();
// => [
// {
// "table": "articles",
// "column": "id"
// },
// {
// "table": "articles",
// "column": "title"
// },
// {
// "table": "images",
// "column": "id"
// }
// ]
await inspector.columns('articles');
// => [
// {
// "table": "articles",
// "column": "id"
// },
// {
// "table": "articles",
// "column": "title"
// }
// ]
columnInfo(table?: string, column?: string): Promise<Column[] | Column>
Retrieve all columns from a given table. Returns all columns if table
parameter is undefined.
await inspector.columnInfo('articles');
// => [
// {
// name: "id",
// table: "articles",
// data_type: "VARCHAR",
// default_value: null,
// max_length: null,
// numeric_precision: null,
// numeric_scale: null,
// is_nullable: false,
// is_unique: false,
// is_primary_key: true,
// has_auto_increment: true,
// foreign_key_column: null,
// foreign_key_table: null,
// comment: "Primary key for the articles collection"
// },
// { ... },
// { ... }
// ]
await inspector.columnInfo('articles', 'id');
// => {
// name: "id",
// table: "articles",
// data_type: "VARCHAR",
// default_value: null,
// max_length: null,
// numeric_precision: null,
// numeric_scale: null,
// is_nullable: false,
// is_unique: false,
// is_primary_key: true,
// has_auto_increment: true,
// foreign_key_column: null,
// foreign_key_table: null,
// comment: "Primary key for the articles collection"
// }
primary(table: string): Promise<string>
Retrieve the primary key column for a given table
await inspector.primary('articles');
// => "id"
Foreign Keys
Retrieve all configured foreign key constraints.
await inspector.foreignKeys();
// => [
// {
// table: 'directus_files',
// column: 'folder',
// foreign_key_table: 'directus_folders',
// foreign_key_column: 'id',
// constraint_name: 'directus_files_folder_foreign',
// on_update: 'CASCADE',
// on_delete: 'SET NULL'
// },
// {
// table: 'directus_files',
// column: 'modified_by',
// foreign_key_table: 'directus_users',
// foreign_key_column: 'id',
// constraint_name: 'directus_files_modified_by_foreign',
// on_update: 'CASCADE',
// on_delete: 'SET NULL'
// }
// ]
Misc.
withSchema(schema: string): void
Not supported in MySQL
Set the schema to use. Note: this is set on the inspector instance and only has to be done once:
inspector.withSchema('my-schema');
Contributing
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
Please make sure to update tests as appropriate.
Tests
First start docker containers:
$ docker-compose up -d
Then run tests:
$ npm test
Standard mocha filter (grep) can be used:
$ npm test -- -g '.tableInfo'
License
MIT