fun main()

in documentation-website/Writerside/snippets/exposed-migrations/src/main/kotlin/org/example/App.kt [24:88]
46 lines of code
1 McCabe index (conditional complexity)

fun main() {
    val h2db = Database.connect(
        url = URL,
        driver = "org.h2.Driver",
        user = USER,
        password = PASSWORD
    )

    val flyway = Flyway.configure()
        .dataSource(URL, USER, PASSWORD)
        .locations("filesystem:$MIGRATIONS_DIRECTORY")
        .baselineOnMigrate(true) // Used when migrating an existing database for the first time
        .load()

    simulateExistingDatabase(h2db)

    transaction(h2db) {
        println("*** Before migration ***")
        println("Primary key: ${currentDialectMetadata.existingPrimaryKeys(UsersTable)[UsersTable]}")

        // Generate a migration script
        generateMigrationScript()
    }

    transaction(h2db) {
        // Generate SQL statements required to align the database schema
        // against the current table definitions
        val statements = MigrationUtils.statementsRequiredForDatabaseMigration(
            UsersTable
        )
        println(statements)

        // Disable logging
        MigrationUtils.statementsRequiredForDatabaseMigration(
            UsersTable,
            withLogs = false
        )

        // Identify columns that are no longer present in the current table definitions
        // and return the SQL statements to remove them
        val dropStatements = MigrationUtils.dropUnmappedColumnsStatements(
            UsersTable
        )
        println(dropStatements)

        // SchemaUtils methods
        val missingColStatements = SchemaUtils.addMissingColumnsStatements(
            UsersTable
        )
        println(missingColStatements)

        // This can be commented out to review the generated migration script before applying a migration
        flyway.migrate()
    }

    transaction(h2db) {
        println("*** After migration ***")
        println("Primary key: ${currentDialectMetadata.existingPrimaryKeys(UsersTable)[UsersTable]}")

        UsersTable.insert {
            it[id] = UUID.randomUUID()
            it[email] = "root2@root.com"
        }
    }
}