tMysqlOutputBulk - 6.3

Talend Open Studio for Big Data Components Reference Guide

EnrichVersion
6.3
EnrichProdName
Talend Open Studio for Big Data
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

The tMysqlOutputBulk and tMysqlBulkExec components are used together in a two step process. In the first step, an output file is generated. In the second step, this file is used in the INSERT statement used to feed a database. These two steps are fused together in the tMysqlOutputBulkExec component, detailed in a separate section. The advantage of using two separate steps is that the data can be transformed before it is loaded in the database.

Function

Writes a file with columns based on the defined delimiter and the MySql standards

Purpose

Prepares the file to be used as parameter in the INSERT query to feed the MySQL database.

tMysqlOutputBulk properties

Component family

Databases/MySQL

 

Basic settings

Property type

Either Built-in or Repository.

Since version 5.6, both the Built-In mode and the Repository mode are available in any of the Talend solutions.

 

 

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.

 

File Name

Name of the file to be generated.

This file is generated on the same machine where the Studio is installed or where the Job using tMysqlOutputBulk is deployed.

 

Append

Select this check box to add the new rows at the end of the file

 

Schema and Edit Schema

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

Since version 5.6, both the Built-In mode and the Repository mode are available in any of the Talend solutions.

 

 

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.

When the schema to be reused has default values that are integers or functions, ensure that these default values are not enclosed within quotation marks. If they are, you must remove the quotation marks manually.

For more details, see the article Verifying default values in a retrieved schema on Talend Help Center (https://help.talend.com).

  

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.

Advanced settings

Row separator

String (ex: "\n" on Unix) to distinguish rows.

 

Field separator

Character, string or regular expression to separate fields.

 

Text enclosure

Character used to enclose the text.

 

Create directory if does not exist

This check box is selected by default. It creates a directory to hold the output table if required.

 

Custom the flush buffer size

Customize the amount of memory used to temporarily store output data. In the Row number field, enter the number of rows after which the memory is to be freed again.

 

Records contain NULL value

This check box is selected by default. It allows you to take account of NULL value fields. If you clear the check box, the NULL values will automatically be replaced with empty values.

 

Check disk space

Select the this check box to throw an exception during execution if the disk is full.

 

Encoding

Select the encoding from the list or select Custom and define it manually. This field is compulsory for DB data handling.

 

tStatCatcher Statistics

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

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 to be used along with tMySQlBulkExec component. Used together they offer gains in performance while feeding a MySQL database.

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.

Limitation

Due to license incompatibility, one or more JARs required to use this component are not provided. You can install the missing JARs for this particular component by clicking the Install button on the Component tab view. You can also find out and add all missing JARs easily on the Modules tab in the Integration perspective of your studio. For details, see the article Installing External Modules on Talend Help Center (https://help.talend.com) how to configure the Studio in the Talend Installation and Upgrade Guide.

Scenario: Inserting transformed data in MySQL database

This scenario describes a four-component job which aims at fueling a database with data contained in a file, including transformed data. Two steps are required in this job, first step is to create the file, that will then be used in the second step. The first step includes a tranformation phase of the data included in the file.

Dropping and linking components

  1. Drag and drop a tRowGenerator, a tMap, a tMysqlOutputBulk as well as a tMysqlBulkExec component.

  2. Connect the main flow using row Main links.

  3. And connect the start component (tRowgenerator in this example) to the tMysqlBulkExec using a trigger connection, of type OnComponentOk.

Configuring the components

  1. A tRowGenerator is used to generate random data. Double-click on the tRowGenerator component to launch the editor.

  2. Define the schema of the rows to be generated and the nature of data to generate. In this example, the clients file to be produced will contain the following columns: ID, First Name, Last Name, Address, City which all are defined as string data but the ID that is of integer type.

    Some schema information don't necessarily need to be displayed. To hide them away, click on Columns list button next to the toolbar, and uncheck the relevant entries, such as Precision or Parameters.

    Use the plus button to add as many columns to your schema definition.

    Click the Refresh button to preview the first generated row of your output.

  3. Then select the tMap component to set the transformation.

  4. Drag and drop all columns from the input table to the output table.

  5. Apply the transformation on the LastName column by adding .toUpperCase() in its expression field.

    Then, click OK to validate the transformation.

  6. Double-click on the tMysqlOutputBulk component.

  7. Define the name of the file to be produced in File Name field. If the delimited file information is stored in the Repository, select it in Property Type field, to retrieve relevant data. In this use case the file name is clients.txt.

    The schema is propagated from the tMap component, if you accepted it when prompted.

  8. In this example, don't include the header information as the table should already contain it.

  9. Click OK to validate the output.

  10. Then double-click on the tMysqlBulkExec component to set the INSERT query to be executed.

  11. Define the database connection details. We recommend you to store this type of information in the Repository, so that you can retrieve them at any time for any Job.

  12. Set the table to be filled in with the collected data, in the Table field.

  13. Fill in the column delimiters in the Field terminated by area.

  14. Make sure the encoding corresponds to the data encoding.

Saving and executing the Job

  1. Press Ctrl+S to save your Job.

  2. Press F6 or click Run on the Run tab to execute the Job.

    The clients database table is filled with data from the file including upper-case last name as transformed in the job.

For simple Insert operations that don't include any transformations, the use of tMysqlOutputBulkExec allows you to skip a step in the process and thus improves performance.

Related topic: tMysqlOutputBulkExec properties