tMSSqlCDC - 6.1

Talend Components Reference Guide

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6.1
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tMSSqlCDC properties

Component family

Databases/MS SQL

 

Function

tMSSqlCDC extracts source system data that has changed since the last extraction and transports it to another/other system(s).

Purpose

tMSSqlCDC addresses data extraction and transportation needs. tMSSqlCDC only extracts the changes made to the source operational data and makes them available to the target system(s) using database CDC views.

Basic Settings

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.

Note

When a Job contains the parent Job and the child Job, if you need to share an existing connection between the two levels, for example, to share the connection created by the parent Job with the child Job, you have to:

  1. In the parent level, register the database connection to be shared in the Basic settings view of the connection component which creates that very database connection.

  2. In the child level, use a dedicated connection component to read that registered database connection.

For an example about how to share a database connection across Job levels, see Talend Studio User Guide.

 

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.

Warning

Reset the DB type by clicking the relevant button to select the CDC connection.

 

Host

Database server IP address.

 

Port

Listening port number of DB server.

 

Database

Name of the database.

 

Schema

Name of the schema.

 

Username and Password

DB 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 using CDC 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.

Warning

Reset the DB type by clicking the relevant button to select the schema of the CDC connection.

  

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

  • View schema: choose this option to view the schema only.

  • Change to built-in property: choose this option to change the schema to Built-in for local changes.

  • Update repository connection: choose this option to change the schema stored in the repository and decide whether to propagate the changes to all the Jobs upon completion. If you just want to propagate the changes to the current Job, you can select No upon completion and choose this schema metadata again in the [Repository Content] window.

 

Table name

Select the source table from which changes made to data are to be captured.

 

Subscriber

Enter the name of the application that will use the change table.

 

Events to catch

Insert: Select this check box to catch the data inserted in the change table since the last extraction.

Update: Select this check box to catch the data updated in the change table since the last extraction.

Delete: Select this check box to catch the data deleted in the change table since the last extraction.

 

Limit

Maximum number of consumed rows a subscriber can recover from the change table, per execution.

Advanced settings

Additional JDBC parameters

Specify additional connection properties for the DB connection you are creating. This option is not available if you have selected the Use an existing connection check box in the Basic settings.

  Keep data in CDC table Select this check box to keep the changes made available to one or more target systems, even after they have been consulted.

 

Trim all the String/Char columns

Select this check box to delete any spaces found at the beginning or end of fields, in all of the columns containing character strings.

 

Trim column

Remove leading and trailing whitespace from defined columns.

Note

Clear Trim all the String/Char columns to enable Trim columns in this field.

 

tStatCatcher Statistics

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

  Enable parallel execution

Select this check box to perform high-speed data processing, by treating multiple data flows simultaneously. Note that this feature depends on the database or the application ability to handle multiple inserts in parallel as well as the number of CPU affected. In the Number of parallel executions field, either:

  • Enter the number of parallel executions desired.

  • Press Ctrl + Space and select the appropriate context variable from the list. For further information, see Talend Studio User Guide.

Note that when parallel execution is enabled, it is not possible to use global variables to retrieve return values in a subjob.

Warning

  • The Action on table field is not available with the parallelization function. Therefore, you must use a tCreateTable component if you want to create a table.

  • When parallel execution is enabled, it is not possible to use global variables to retrieve return values in a subjob.

Global Variables 

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

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 is used as a start component. It requires an output component and row Main link.

Log4j

If you are using a subscription-based version of the Studio, 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.

Related scenario

For a related scenario, see Scenario 2: Retrieving modified data using CDC.