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jdbc-component.adoc

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JDBC

Since Camel 1.2

Only producer is supported

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

Note
 When you use Spring and need to support Spring Transactions, use the Spring JDBC Component instead of this one.

Maven users will 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>

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

Usage

Result

By default, 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. You can use the option outputType to control the result.

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

Generated keys

If you insert data using SQL INSERT, then the RDBMS may support auto generated keys. You can instruct the JDBC producer to return the generated keys in headers.
To do that set the header CamelRetrieveGeneratedKeys=true. Then the generated keys will be provided as headers with the keys listed in the table above.

Using generated keys does not work together with named parameters.

Using named parameters

In the given route below, we want to get all the projects from the projects table. Notice the SQL query has two named parameters, :?lic and :?min. Camel will then look up these parameters from the message headers. Notice in the example above we set two headers with constant value for the named parameters:

  from("direct:projects")
     .setHeader("lic", constant("ASF"))
     .setHeader("min", constant(123))
     .setBody("select * from projects where license = :?lic and id > :?min order by id")
     .to("jdbc:myDataSource?useHeadersAsParameters=true")

You can also store the header values in a java.util.Map and store the map on the headers with the key CamelJdbcParameters.

Examples

In the following example, we set up the DataSource that camel-jdbc requires. First we register our datasource in the Camel registry as testdb:

EmbeddedDatabase db = new EmbeddedDatabaseBuilder()
      .setType(EmbeddedDatabaseType.DERBY).addScript("sql/init.sql").build();

CamelContext context = ...
context.getRegistry().bind("testdb", db);

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:

from("direct:hello")
    .to("jdbc:testdb");

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:

Endpoint endpoint = context.getEndpoint("direct:hello");
Exchange exchange = endpoint.createExchange();
// then we set the SQL on the in body
exchange.getMessage().setBody("select * from customer order by ID");
// now we send the exchange to the endpoint, and receive the response from Camel
Exchange out = template.send(endpoint, exchange);

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
// the StreamList option allows streaming the result of the query without creating a List of rows
// and notice we also enable streaming mode on the splitter
.to("jdbc:testdb?outputType=StreamList")
  .split(body()).streaming()
  .to("mock:result");

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");

Move Data Between Data Sources

A common use case is to query for data, process it and move it to another data source (ETL operations). In the following example, we retrieve new customer records from the source table every hour, filter/transform them and move them to a destination table:

from("timer://MoveNewCustomersEveryHour?period=3600000")
    .setBody(constant("select * from customer where create_time > (sysdate-1/24)"))
    .to("jdbc:testdb")
    .split(body())
        .process(new MyCustomerProcessor()) //filter/transform results as needed
        .setBody(simple("insert into processed_customer values('${body[ID]}','${body[NAME]}')"))
        .to("jdbc:testdb");

spring-boot:partial$starter.adoc