Connection

This chapter describes how to build a connection to connect to a database.

To connect to a database, a connection must be established. A connection is a resource that manages the connection to the database. A connection provides the resources to initiate a connection to the database, execute a query, and close the connection.

ldbc connects to the database using either jdbc or ldbc's own connector. Which one to use depends on the dependencies you set up.

Use jdbc connector

First, add the dependencies.

If you use the JDJD connector, you must also add the MySQL connector.

//> dep "io.github.takapi327::jdbc-connector:0.3.0-beta8"
//> dep "com.mysql":"mysql-connector-j":"8.4.0"

Next, create a data source using MysqlDataSource.

val ds = new com.mysql.cj.jdbc.MysqlDataSource()
ds.setServerName("127.0.0.1")
ds.setPortNumber(13306)
ds.setDatabaseName("world")
ds.setUser("ldbc")
ds.setPassword("password")

Create a jdbc connector data source using the data source you created.

val datasource = jdbc.connector.MysqlDataSource[IO](ds)

Finally, a connection is created using a jdbc connector.

val connection: Resource[IO, Connection[IO]] =
  Resource.make(datasource.getConnection)(_.close())

Here we use the Cats Effect Resource to close the connection after it has been used.

Use ldbc connector

First, add dependencies.

//> dep "io.github.takapi327::ldbc-connector:0.3.0-beta8"

Next, Tracer is provided. ldbc connectors use Tracer to collect telemetry data. These are used to record application traces.

Here, Tracer is provided using Tracer.noop.

given Tracer[IO] = Tracer.noop[IO]

Finally, create a Connection.

val connection: Resource[IO, Connection[IO]] =
  ldbc.connector.Connection[IO](
    host     = "127.0.0.1",
    port     = 3306,
    user     = "ldbc",
    password = Some("password"),
    database = Some("ldbc")
  )

The parameters for setting up a connection are as follows