repo_description: GoCQL Driver for Apache Cassandra®
repo_topics: cassandra client database driver go golang nosql
code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * Content before git sha 34fdeebefcbf183ed7f916f931aa0586fdaa1b40
   * Copyright (c) 2016, The Gocql authors,
   * provided under the BSD-3-Clause License.
   * See the NOTICE file distributed with this work for additional information.
   */
  
  package gocql_test
  
  import (
  	"context"
  	"fmt"
  	"log"
  
  	gocql "github.com/apache/cassandra-gocql-driver/v2"
  )
  
  type MyUDT struct {
  	FieldA string `cql:"field_a"`
  	FieldB int32  `cql:"field_b"`
  }
  
  // Example_userDefinedTypesStruct demonstrates how to work with user-defined types as structs.
  // See also examples for UDTMarshaler and UDTUnmarshaler if you need more control/better performance.
  func Example_userDefinedTypesStruct() {
  	/* The example assumes the following CQL was used to setup the keyspace:
  	create keyspace example with replication = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
  	create type example.my_udt (field_a text, field_b int);
  	create table example.my_udt_table(pk int, value frozen<my_udt>, PRIMARY KEY(pk));
  	*/
  	cluster := gocql.NewCluster("localhost:9042")
  	cluster.Keyspace = "example"
  	cluster.ProtoVersion = 4
  	session, err := cluster.CreateSession()
  	if err != nil {
  		log.Fatal(err)
  	}
  	defer session.Close()
  
  	ctx := context.Background()
  
  	value := MyUDT{
  		FieldA: "a value",
  		FieldB: 42,
  	}
  	err = session.Query("INSERT INTO example.my_udt_table (pk, value) VALUES (?, ?)",
  		1, value).ExecContext(ctx)
  	if err != nil {
  		log.Fatal(err)
  	}
  
  	// Read the UDT value back
  	var readValue MyUDT
  	err = session.Query("SELECT value FROM example.my_udt_table WHERE pk = 1").ScanContext(ctx, &readValue)
  	if err != nil {
  		log.Fatal(err)
  	}
  	fmt.Println(readValue.FieldA)
  	fmt.Println(readValue.FieldB)
  	// a value
  	// 42
  }
  