tJDBCInput – Docs for ESB 5.x

Component family

Databases/JDBC

Function

tJDBCInput reads any database
using a JDBC API connection and extracts fields based on a query.

If you have subscribed to one of the Talend solutions with Big Data, you are
able to use this component in a Talend Map/Reduce Job to generate
Map/Reduce code. In that situation, tJDBCInput belongs to the MapReduce component
family. For further information, see tJDBCInput in Talend Map/Reduce
Jobs.

Purpose

tJDBCInput executes a database
query with a strictly defined order which must correspond to the
schema definition. Then it passes on the field list to the next
component via a Main row link.

Basic settings

Property type

Either Built-in or
Repository.

Built-in: No property data stored
centrally.

Repository: Select the repository
file in which the properties are stored. The fields that follow are
completed automatically using the data retrieved.

Use an existing connection

Select this check box and in the Component List click the
relevant connection component to reuse the connection details you already defined.

Click this icon to open a database connection wizard and store the
database connection parameters you set in the component Basic settings view.

For more information about setting up and storing database
connection parameters, see Talend Studio User Guide.

JDBC URL

Type in the database location path.

Driver JAR

Click the plus button under the table to add lines of the count of
your need for the purpose of loading several JARs. Then on each
line, click the three dot button to open the [Select Module] wizard from which you can select a
driver JAR of your interest for each line.

Class Name

Type in the Class name to be pointed to in the driver.

Username and
Password

Database user authentication data.

To enter the password, click the […] button next to the
password field, and then in the pop-up dialog box enter the password between double quotes
and click OK to save the settings.

Schema and Edit
schema

A schema is a row description. It defines the number of fields to be processed and passed on
to the next component. The schema is either Built-In or
stored remotely in the Repository.

This component offers the advantage of the dynamic schema feature. This allows you to
retrieve unknown columns from source files or to copy batches of columns from a source
without mapping each column individually. For further information about dynamic schemas,
see Talend Studio
User Guide.

This dynamic schema feature is designed for the purpose of retrieving unknown columns
of a table and is recommended to be used for this purpose only; it is not recommended
for the use of creating tables.

Built-In: You create and store the schema locally for this
component only. Related topic: see Talend Studio
User Guide.

Repository: The schema already
exists and is stored in the Repository, hence can be reused. Related
topic: see Talend Studio User
Guide.

Click Edit schema to make changes to the schema. If the
current schema is of the Repository type, three options are
available:

Table Name

Type in the name of the table.

Query type and
Query

Enter your database query paying particularly attention to
properly sequence the fields in order to match the schema
definition.

Specify a data source alias

Select this check box and specify the alias of a data source created on the Talend Runtime side to use the shared connection pool defined in the data source configuration.
This option works only when you deploy and run your Job in Talend Runtime.

This check box is not available when the Use an existing
connection check box is selected.

Advanced settings

Use cursor

When selected, helps to decide the row set to work with at a time
and thus optimize performance.

Trim all the String/Char columns

Select this check box to remove leading and trailing whitespace
from all the String/Char columns.

Trim column

Remove leading and trailing whitespace from defined
columns.

Enable Mapping File for Dynamic

Select this check box to use the specified metadata mapping file
when reading data from a dynamic type column. This check box is
cleared by default.

For more information about metadata mapping files, see the section
on type conversion of Talend Studio User
Guide.

Mapping File

Specify the metadata mapping file to use by selecting a type of
database from the list.

This list field appears only when the Enable
Mapping File for Dynamic check box is
selected.

tStatCatcher Statistics

Select this check box to collect log data at the component
level.

Dynamic settings

Click the [+] button to add a row in the table and fill
the Code field with a context variable to choose your
database connection dynamically from multiple connections planned in your Job. This feature
is useful when you need to access database tables having the same data structure but in
different databases, especially when you are working in an environment where you cannot
change your Job settings, for example, when your Job has to be deployed and executed
independent of Talend Studio.

The Dynamic settings table is available only when the
Use an existing connection check box is selected in the
Basic settings view. Once a dynamic parameter is
defined, the Component List box in the Basic settings view becomes unusable.

For more information on Dynamic settings and context
variables, see Talend Studio User Guide.

Global Variables

NB_LINE: the number of rows processed. This is an After
variable and it returns an integer.

QUERY: the SQL query statement being processed. This is a
Flow variable and it returns a string.

ERROR_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error check box is
cleared, if the component has this check box.

A Flow variable functions during the execution of a component while an After variable
functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl +
Space to access the variable list and choose the variable to use from it.

For further information about variables, see Talend Studio
User Guide.

Usage

This component covers all possible SQL queries for any database
using a JDBC connection.

Log4j

The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User
Guide.

For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.

Component family

MapReduce/Input

Basic settings

Property type

Either Built-in or
Repository.

Built-in: No property data stored
centrally.

Repository: Select the repository
file in which the properties are stored. The fields that follow are
completed automatically using the data retrieved.

Click this icon to open a database connection wizard and store the
database connection parameters you set in the component Basic settings view.

For more information about setting up and storing database
connection parameters, see Talend Studio User Guide.

JDBC URL

Type in the database location path. For example, if a MySQL
database called Talend is hosted
by a machine located at an IP address XX.XX.XX.XX and the port is 3306, then the URL should be jdbc:mysql://XX.XX.XX.XX:3306/Talend.

Driver JAR

Click the plus button under the table to add lines of the count of
your need for the purpose of loading several JARs. Then on each
line, click the three dot button to open the [Select Module] wizard from which you can select a
driver JAR of your interest for each line.

Class Name

Type in the Class name to be pointed to in the driver. For
example, for the mysql-connector-java-5.1.2.jar driver, the name to
be entered is org.gjt.mm.mysql.Driver.

Username and
Password

Database user authentication data.

To enter the password, click the […] button next to the
password field, and then in the pop-up dialog box enter the password between double quotes
and click OK to save the settings.

Schema and Edit
schema

A schema is a row description. It defines the number of fields to be processed and passed on
to the next component. The schema is either Built-In or
stored remotely in the Repository.

Built-In: You create and store the schema locally for this
component only. Related topic: see Talend Studio
User Guide.

Repository: You have already created the schema and
stored it in the Repository. You can reuse it in various projects and Job designs. Related
topic: see Talend Studio User Guide.

Click Edit schema to make changes to the schema. If the
current schema is of the Repository type, three options are
available:

Table Name

Type in the name of the table from which you need to read
data.

Die on error

Select this check box to stop the execution of the Job when an error occurs.

Clear the check box to skip any rows on error and complete the process for error-free rows.
When errors are skipped, you can collect the rows on error using a Row
> Reject link.

Query type and
Query

Enter your database query paying particularly attention to
properly sequence the fields in order to match the schema
definition.

Usage

In a Talend Map/Reduce Job, it is used as a start component and requires
a transformation component as output link. The other components used along with it must be
Map/Reduce components, too. They generate native Map/Reduce code that can be executed
directly in Hadoop.

For further information about a Talend Map/Reduce Job, see the sections
describing how to create, convert and configure a Talend Map/Reduce Job of the
Talend Big Data Getting Started Guide.

Note that in this documentation, unless otherwise explicitly stated, a scenario presents
only Standard Jobs, that is to say traditional Talend data
integration Jobs, and non Map/Reduce Jobs.

Hadoop Connection

You need to use the Hadoop Configuration tab in the
Run view to define the connection to a given Hadoop
distribution for the whole Job.

This connection is effective on a per-Job basis.

Limitation

We recommend using the following databases with the Map/Reduce
version of this component: DB2, Informix, MSSQL, MySQL, Netezza,
Oracle, Postgres, Teradata and Vertica.

It may work with other databases as well, but these may not
necessarily have been tested.