Creating a Multi-DB config
The following params are available when creating your Multi-DB config file or passing params via the constructor:
Required params
default[String]: Which database your app will use by default.- Available options:
mariadbmysqlpostgrespglitesqlite
- Available options:
[mariadb|mysql|postgres|pglite|sqlite][Object]: Configs specific to each database.config[Object]: Which config to attempt to connect to your database with by default. This object will be passed directly to the database driver, so the values should be set to whatever the database driver expects you to use to connect (e.g. host, username, password, database, other database configuration options).- It is recommended that you set the user to a less privileged user, typically meaning this user should be able to insert and delete data, but not create, alter, or drop tables.
- If the credentials you specify do not exist, they can be created from the CLI scripts, which will use the
adminConfigto connect in order to create the less privileged credentials.
adminConfig[Object]: Same asconfigbut you should configure it to use more privileged credentials, e.g. an account that is authorized to create tables, drop tables, administrate other users, etc. This config will be used for the CLI scripts for setup and teardown tasks. The regular, typically less-privileged config will be used for your app's business logic.
Optional params
admin[Boolean]: Force the use ofadminConfigfor your database instead of the regularconfig. Default:false.schema[String]: Relative path to a file with what set of SQL statements you want to execute against your database when it is freshly created, if any. Default:undefined.loggerConfig[Object]: Options to suppress various kinds of logging.
Default:
loggerConfig: {
log: true, // regular logs
error: true, // logging errors
verbose: true // verbose logging
}questionMarkParamsForPostgres[Boolean]: Automatically convert parameterized query placeholders from?to$ + numberwithin Multi-DB for PostgreSQL queries so you can use the?syntax in PostgreSQL queries, which isn't possible in native PostgreSQL queries. Default:true.mergeConfig[Boolean]: Merge config values passed via constructor or environment variable with any.multi-db-config.jsonfile detected in your app's directory structure. Default:true.
Example configs
Example for MariaDB:
{
"default": "mariadb",
"mariadb": {
"config": {
"host": "localhost",
"port": 3306,
"user": "app_name",
"password": "app_password",
"database": "app_name"
},
"adminConfig": {
"host": "localhost",
"port": 3306,
"user": "root",
"password": "password",
"database": "mariadb"
},
"schema": "db/schema.sql"
}
}Example for MySQL:
{
"default": "mysql",
"mysql": {
"config": {
"host": "localhost",
"port": 3306,
"user": "app_name",
"password": "app_password",
"database": "app_name"
},
"adminConfig": {
"host": "localhost",
"port": 3306,
"user": "root",
"password": "password",
"database": "mysql"
},
"schema": "db/schema.sql"
}
}Example for PostgreSQL:
{
"default": "postgres",
"postgres": {
"config": {
"host": "localhost",
"port": 5432,
"user": "app_name",
"password": "app_password",
"database": "app_name"
},
"adminConfig": {
"host": "localhost",
"port": 5432,
"username": "admin",
"password": "admin_password",
"database": "postgres"
},
"schema": "db/schema.sql"
}
}Example for PGlite:
{
"default": "pglite",
"pglite": {
"config": {
"database": "pg-data"
},
"schema": "db/schema.sql"
}
}Example for SQLite:
{
"default": "sqlite",
"sqlite": {
"config": {
"database": "db.sqlite"
},
"schema": "db/schema.sql"
}
}You could also create a single config that has configs for multiple databases or all of them if you like, but only one can be connected to per instance of Multi-DB.
Multi-DB API
When you connect to a database using Multi-DB like in the below example, the constructor will return a db object.
const db = await require('multi-db-driver')(config)This is the structure of the db object that Multi-DB returns:
db.query(...)[Function]: Universal database query method that works on all supported databases.- Arguments you can pass:
query[String or Object]:- When supplied a string as an argument, it will execute the query string against the default driver.
- When supplied an object as an argument, you can supply the following keys:
default: A query string to execute against whichever database is the default.mariadb: A query string that will only execute against MariaDB databases.mysql: A query string that will only execute against MySQL databases.postgres: A query string that will only execute against PostgreSQL databases.pglite: A query string that will only execute against SQLite databases.sqlite: A query string that will only execute against SQLite databases.disableQuestionMarkParamsForPostgres: Set to true to prevent the query from attempting to normalize parameterized query placeholders from?syntax to$1 $2 $3 etcsyntax for PostgreSQL and PGlite queries.
params[Array of Strings]: Optional array of parameters to supply values to the query.next(db, result)[Function]: Optional callback function to execute when the query is finished.- Arguments provided:
db[String]: Which database the query was executed against.result[Object]: The resulting object from the query the database driver gives you.
- Arguments provided:
- Arguments you can pass:
db.config[Object]: Object representing the config loaded.db.driver[Object]: The object the default database driver module returns in case you need to interact with it directly.db.drivers[Object]: Object collection of all the driver modules currently loaded.db.mariadb[Object]: MariaDB-specific APIs.driver[Object]: The object themariadbmodule returns in case you need to interact with it directly.pool[Object]: The pool instance returned by mariadb's createPool method once instantiated.conn[Object]: The connection instance returned by the pool instance's getConnection method once instantiated.username[String]: Username of the current active connection, if a connection is active.database[String]: Which database the currently active connection is connected to, if a connection is active.query(queryString)[Function]: Function that takes a query string and executes it against themariadbdriver.
db.mysql[Object]: MySQL-specific APIs.driver[Object]: The object themysql2module returns in case you need to interact with it directly.pool[Object]: The pool instance returned by mysql2's createPool method once instantiated.conn[Object]: The connection instance returned by the pool instance's getConnection method once instantiated.username[String]: Username of the current active connection, if a connection is active.database[String]: Which database the currently active connection is connected to, if a connection is active.query(queryString)[Function]: Function that takes a query string and executes it against themysql2driver.
db.postgres[Object]: PostgreSQL-specific APIs.driver[Object]: The object thepgmodule returns in case you need to interact with it directly.pool[Object]: The instance of pg.Pool created by Multi-DB once instantiated.client[Object]: The instance of pg.Client created by Multi-DB once instantiated.username[String]: Username of the current active connection, if a connection is active.database[String]: Which database the currently active connection is connected to, if a connection is active.query(queryString)[Function]: Function that takes a query string and executes it against thepgdriver.
db.pglite[Object]: PGlite-specific APIs.driver[Object]: The object the@electric-sql/pglitemodule returns in case you need to interact with it directly.db[Object]: The database instance returned by @electric-sql/pglite's Database constructor once instantiated.query(queryString)[Function]: Function that takes a query string and executes it against the@electric-sql/pglitedriver.
db.sqlite[Object]: SQLite-specific APIs.driver[Object]: The object thebetter-sqlite3module returns in case you need to interact with it directly.db[Object]: The database instance returned by better-sqlite3's Database constructor once instantiated.query(queryString)[Function]: Function that takes a query string and executes it against thebetter-sqlite3driver.