# JDBC

## JDBC Component

The jdbc component enables you to access databases through JDBC, where SQL queries and operations are sent in the message body. This component uses the standard JDBC API, unlike the SQL Component component, which uses spring-jdbc.

Maven users need to add the following dependency to their `pom.xml` for this component:

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-jdbc</artifactId>
        <version>x.x.x</version>
        <!-- use the same version as your Camel core version -->
    </dependency>

| Warning
This component can only be used to define producer endpoints, which means that you cannot use the JDBC component in a `from()` statement.

| Important
This component cannot be used as a transactional client. If you need transaction support in your route, use the SQL Component component instead.

## URI format

    jdbc:dataSourceName[?options]

This component supports producer endpoints only.

You can append query options to the URI in the following format, `?option=value&option=value&...`

## Options

Name | Default Value | Description
--- | --- | ---
`readSize` | `0` / `2000` | The default maximum number of rows that can be read by a polling query. The default value is 2000 for Apache Camel 1.5.0 or older. In newer releases the default value is 0.
`statement.<xxx>` | `null` | Apache Camel 2.1: Sets additional options on the `java.sql.Statement` that is used behind the scenes to execute the queries. For instance, `statement.maxRows=10`. For detailed documentation, see the `java.sql.Statement` javadoc documentation.
`useJDBC4ColumnNameAndLabelSemantics` | `true` | Apache Camel 2.2: Sets whether to use JDBC 4/3 column label/name semantics. You can use this option to turn it `false` in case you have issues with your JDBC driver to select data. This only applies when using `SQL SELECT` using aliases (e.g. `SQL SELECT id as identifier, name as given_name from persons`).
`resetAutoCommit` | `true` | Apache Camel 2.9: When `true`, Camel sets the autoCommit flag on the JDBC connection to `false`, commits the change after executing the statement, and resets the connection's autoCommit flag to `true` at the end of the operation. If the JDBC connection does not support resetting the autoCommit flag, set this option to `false` to prevent Camel from trying to set the connection's autoCommit flag.

## Result

The result is returned in the OUT body as an `ArrayList<HashMap<String, Object>>`. The `List` object contains the list of rows and the `Map` objects contain each row with the `String` key as the column name.

| Note
This component fetches `ResultSetMetaData` to be able to return the column name as the key in the `Map`.

## Message Headers

Header | Description
--- | ---
`CamelJdbcRowCount` | If the query is a `SELECT`, the row count is returned in this OUT header.
`CamelJdbcUpdateCount` | If the query is an `UPDATE`, the update count is returned in this OUT header.
`CamelGeneratedKeysRows` | Apache Camel 2.10: Rows that contain the generated keys.
`CamelGeneratedKeysRowCount` | Apache Camel 2.10: The number of rows in the header that contain generated keys.

## Generated Keys

Available as of 2.10.

The RDBMS may support autogenerated keys if you insert data using SQL INSERT. If so, you can instruct the JDBC producer to return the generated keys in headers. To do so, set the header `CamelRetrieveGenerateKeys=true`, and then the generated keys will be returned as headers with the keys listed in Message Headers.

## Samples

In the following example, we fetch the rows from the customer table.

First we register our datasource in the Apache Camel registry as `testdb`:

    JndiRegistry reg = super.createRegistry();
    reg.bind("testdb", ds);
    return reg;

Then we configure a route that routes to the JDBC component, so the SQL will be executed. Note how we refer to the `testdb` datasource that was bound in the previous step:

    // lets add simple route
    public void configure() throws Exception {
        from("direct:hello").to("jdbc:testdb?readSize=100");
    }

Or you can create a `DataSource` in Spring like this:

    <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
      <route>
         <from uri="timer://kickoff?period=10000"/>
         <setBody>
           <constant>select * from customer</constant>
         </setBody>
         <to uri="jdbc:testdb"/>
         <to uri="mock:result"/>
      </route>
    </camelContext>
    <!-- Just add a demo to show how to bind a date source for camel in Spring-->
    <bean id="testdb" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    	<property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
    	<property name="url" value="jdbc:hsqldb:mem:camel_jdbc" />
    	<property name="username" value="sa" />
      <property name="password" value="" />
    </bean>

We create an endpoint, add the SQL query to the body of the IN message, and then send the exchange. The result of the query is returned in the OUT body:

    // first we create our exchange using the endpoint
    Endpoint endpoint = context.getEndpoint("direct:hello");
    Exchange exchange = endpoint.createExchange();
    // then we set the SQL on the in body
    exchange.getIn().setBody("select * from customer order by ID");

    // now we send the exchange to the endpoint, and receives the response from Camel
    Exchange out = template.send(endpoint, exchange);

    // assertions of the response
    assertNotNull(out);
    assertNotNull(out.getOut());
    ArrayList<HashMap<String, Object>> data = out.getOut().getBody(ArrayList.class);
    assertNotNull("out body could not be converted to an ArrayList - was: "
        + out.getOut().getBody(), data);
    assertEquals(2, data.size());
    HashMap<String, Object> row = data.get(0);
    assertEquals("cust1", row.get("ID"));
    assertEquals("jstrachan", row.get("NAME"));
    row = data.get(1);
    assertEquals("cust2", row.get("ID"));
    assertEquals("nsandhu", row.get("NAME"));

If you want to work on the rows one by one instead of the entire ResultSet at once you need to use the Splitter EIP such as:

    from("direct:hello")
            // here we split the data from the testdb into new messages one by one
            // so the mock endpoint will receive a message per row in the table
        .to("jdbc:testdb").split(body()).to("mock:result");

## Sample - Polling the database every minute

If we want to poll a database using the JDBC component, we need to combine it with a polling scheduler such as the Timer or Quartz etc. In the following example, we retrieve data from the database every 60 seconds:

    from("timer://foo?period=60000").setBody(constant("select * from customer")).to("jdbc:testdb").to("activemq:queue:customers");

See also:

- SQL