components/camel-jdbc/src/main/docs/jdbc-component.adoc

= JDBC Component
:doctitle: JDBC
:shortname: jdbc
:artifactid: camel-jdbc
:description: Access databases through SQL and JDBC.
:since: 1.2
:supportlevel: Stable
:tabs-sync-option:
:component-header: Only producer is supported
//Manually maintained attributes
:camel-spring-boot-name: jdbc

*Since Camel {since}*

*{component-header}*

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
xref:sql-component.adoc[SQL Component] component, which uses
spring-jdbc.

NOTE: Use the xref:spring-jdbc-component.adoc[Spring JDBC Component] instead of this component,
when you use Spring and need to support Spring Transactions.

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

[source,xml]
----
<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.

== URI format

----
jdbc:dataSourceName[?options]
----


// component-configure options: START

// component-configure options: END

// component options: START
include::partial$component-configure-options.adoc[]
include::partial$component-endpoint-options.adoc[]
// component options: END

// endpoint options: START

// endpoint options: END

// component headers: START
include::partial$component-endpoint-headers.adoc[]
// component headers: END

== 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 xref:jdbc-component.adoc[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 with 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 2 named parameters, :?lic and
:?min. +
 Camel will then lookup these parameters from the message headers.
Notice in the example above we set two headers with constant value
 for the named parameters:

[source,java]
----
  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`.

== Samples

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

[source,java]
----
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:

[source,java]
----
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:

[source,java]
----
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 receives 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:

[source,java]
----
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 to stream 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");
----

== 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 xref:timer-component.adoc[Timer]
or xref:quartz-component.adoc[Quartz] etc. In the following example, we retrieve
data from the database every 60 seconds:

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

== Sample - 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:

[source,java]
----
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");
----



include::spring-boot:partial$starter.adoc[]