JDBC Feature Store¶

The ff4k-store-jdbc module provides a JDBC-based FeatureStore implementation for relational databases on the JVM.

Supported Databases¶

PostgreSQL
MySQL

Installation¶

Add the dependency and your database driver:

dependencies {
    implementation("com.yonatankarp:ff4k-store-jdbc:<version>")

    // Database driver (choose one)
    runtimeOnly("org.postgresql:postgresql:<version>")
    runtimeOnly("com.mysql:mysql-connector-j:<version>")
}

Usage¶

Basic Usage¶

Pass a DataSource to create a store. The database type is detected automatically:

val dataSource = HikariDataSource(config)
val store = jdbcFeatureStore(dataSource)

store += Feature(uid = "my-feature", isEnabled = true)

Explicit Dialect¶

For database proxies or when auto-detection fails, use <DatabaseName>Dialect:

val store = jdbcFeatureStore(dataSource, PostgresDialect)

Custom Serializers¶

For custom FlippingStrategy or Property implementations:

val customModule = SerializersModule {
    polymorphic(FlippingStrategy::class) {
        subclass(MyCustomStrategy::class)
    }
}

val store = jdbcFeatureStore(dataSource, customModule)

Features¶

Automatic schema creation - Table created on first use
Optimistic locking - Safe concurrent updates with retry
Connection pooling - Bring your own DataSource (HikariCP recommended)