PostgreSQL is the default database driver that Strontium uses and is the best supported way of using the framework.
Out of the box Strontium includes full support for PostgreSQL connection pooling, SSL and some additional advanced functionality.
Extends Runtime Implements SQLStore
The PGStore object is a Strontium Process that implements SQLStore and provides access to Postgres.
As PGStore is itself a Process it's important to register the object in the Runtime.
The first argument to PGStore is the connection options which are passed directly to node-postgres. Some common and useful configuration settings are illustrated below.
N.B Creating a PGStore instance does not automatically open a connection.
No connections will be opened until .startup is called.
Attempting to use a store that has not had startup called will result in an error.
new PGStore({
host: "127.0.0.1", // The hostname of the Postgres Server
port: 1234, // The port that the Postgres Server is available on
user: "strontium", // The username to authenticate to Postgres with
password: "SuperSecret", // The password to authenticate to Postgres with
database: "strontium", // The database to connect to in Postgres
min: 5, // The minimum number of open connections to Postgres that should be in the Pool
max: 30, // The maximum number of open connection to Postgres that should be in the Pool
})The query method is used to send queries to the SQL server.
The first argument is the text to be sent to PostgreSQL. This text will not be escaped and care should be taken to avoid passing values which could be used for SQL injection into this parameter.
The second argument is the parameters to pass with the query into PostgreSQL. More information about using parametrized queries can be found in the PostgresQL documentation.
The generic parameter allows the developer to pass in the expected format of the response from PostgreSQL so that the response of the function has this type.
The response is an array of objects from the datastore that fulfill the query.
The createTransaction method is used to open a new SQL Transaction and return an object that represents it.
The first argument is an option PGIsolationLevel enum that allows the developer to select the transaction serialization
level they would like to use. The default value is PGIsolationLevel.READ_COMMITED and is appropriate for most use cases.
The response is a PGTransaction object that represents the newly opened transaction.
The PGTransaction object represents a SQL transaction in PostgreSQL.
The first argument to PGTransaction is the underlying node-pg connection that it is to operate on.
It is the responsibility of the instantiating component to ensure that the connection is properly established as a transaction
in PostgreSQL and that the connection is not shared with another object.
The second argument is an optional logger instance to which the transaction will log lifecycle events such as being opened and closed alongside it's unique transaction ID. This can be helpful for debugging issues where transactions are not released.
The query method is used to send queries to the PostgreSQL server over the transaction.
It's use is identical to that of the PGStore itself - documentation for which can be found above.
The commit method is used to commit the changes that have been performed in the transaction to the PostgreSQL database.
This method also returns the connection to the pool meaning that it is not safe to continue using the PGTransaction after commit has been called.
N.B Attempting to use rollback on a transaction where rollback or commit has already been called will return an error.
The rollback method is used to rollback the changes that have been performed in the transaction to the PostgreSQL database.
This method also returns the connection to the pool meaning that it is not safe to continue using the PGTransaction after rollback has been called.
N.B Attempting to use rollback on a transaction where rollback or commit has already been called will return an error.