tAmazonMysqlInput - 6.1

Talend Components Reference Guide

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6.1
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Talend Big Data
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Data Governance
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Talend Studio

tAmazonMysqlInput properties

Component family

Cloud/AmazonRDS/MySQL

 

Function

tAmazonMysqlInput reads a database and extracts fields based on a query.

Purpose

tAmazonMysqlInput executes a DB 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.

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.

 

DB Version

MySQL 5 is available.

 

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.

 

Host

Database server IP address.

 

Port

Listening port number of DB server.

 

Database

Name of the database.

 

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 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.

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

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: The schema is created and stored 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.

 

Table Name

Name of the table to be read.

 

Query type and Query

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

Warning

If using the dynamic schema feature, the SELECT query must include the * wildcard, to retrieve all of the columns from the table selected.

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.

Note

When you need to handle data of the time-stamp type 0000-00-00 00:00:00 using this component, set the parameter as:

noDatetimeStringSync=true&zeroDa√ā¬≠teTimeBehavior=convertToNull.

 

Enable stream

Select this check box to enables streaming over buffering which allows the code to read from a large table without consuming a large amount of memory in order to optimize the 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.

Note

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

 

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 examples on using dynamic parameters, see Scenario 3: Reading data from MySQL databases through context-based dynamic connections and Scenario: Reading data from different MySQL databases using dynamically loaded connection parameters. For more information on Dynamic settings and context variables, see Talend Studio User Guide.

Global Variables

NB_LINE: the number of rows read by an input component or transferred to an output component. 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 Mysql databases.

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.

Scenario 1: Writing columns from a MySQL database to an output file

In this scenario we will read certain columns from a MySQL database, and then write them to a table in a local output file.

Setting up the Job

  1. Drop tAmazonMysqlInput and tFileOutputDelimited from the Palette onto the workspace.

  2. Link tAmazonMysqlInput to tFileOutputDelimited using a Row > Main connection.

Configuring the input component

  1. Double-click tAmazonMysqlInput to open its Basic Settings view in the Component tab.

  2. From the Property Type list, select Repository if you have already stored the connection to database in the Metadata node of the Repository tree view. The property fields that follow are automatically filled in.

    For more information about how to store a database connection, see Talend Studio User Guide.

    If you have not defined the database connection locally in the Repository, fill in the details manually after selecting Built-in from the Property Type list.

  3. Set the Schema as Built-in and click Edit schema to define the desired schema.

    The schema editor opens:

  4. Click the [+] button to add the rows that you will use to define the schema, four columns in this example id, first_name, city and salary.

  5. Under Column, click in the fields to enter the corresponding column names.

  6. Click the field under Type to define the type of data. Click OK to close the schema editor.

  7. Next to the Table Name field, click the [...] button to select the database table of interest.

    A dialog box displays a tree diagram of all the tables in the selected database:

  8. Click the table of interest and then click OK to close the dialog box.

  9. Set the Query Type to Built-In. In the Query box, enter the query required to retrieve the desired columns from the table.

Configuring the output component

  1. Double-click tFileOutputDelimited to set its Basic Settings in the Component tab.

  2. Next to the File Name field, click the [...] button to browse your directory to where you want to save the output file, then enter a name for the file.

  3. Select the Include Header check box to retrieve the column names as well as the data.

Job execution

Save the Job and press F6 to run it.

The output file is written with the desired column names and corresponding data, retrieved from the database:

Note

The Job can also be run in the Traces Debug mode, which allows you to view the rows as they are being written to the output file, in the workspace.

Scenario 2: Writing dynamic columns from a MySQL database to an output file

Warning

This scenario makes use of the Dynamic Schema feature, which is only available to users who have subscribed to one of the Talend solutions.

In this scenario we will read dynamic columns from a MySQL database, map them and then write them to a table in a local output file. By defining a dynamic column alongside known column names, we can retrieve all of the columns from the database table, including the unknown columns.

Setting up the Job

  1. Drop a tAmazonMysqlInput, a tMap and a tFileOutputDelimited component onto the workspace.

  2. Link tAmazonMysqlInput to tMap using a Row > Main connection. Link tMap to tFileOutputDelimited using a Row > *New Output* (Main) connection.

Configuring the input component

  1. Double-click tAmazonMysqlInput to open its Basic settings view in the Component tab.

    Warning

    The dynamic schema feature is only supported in Built-In mode.

  2. Select Built-in as the Property Type. Select the DB Version from the corresponding list.

  3. Next to Host, enter the database server IP address. Next to Port, enter the listening port number of the database server.

  4. Enter your authentication data in the Username and Password fields. Set the Schema type as Built-in and click Edit schema to define the dynamic schema.

    The schema editor opens:

  5. Click the [+] button to add a row to the schema. Under Column, click in the fields to enter the corresponding column names.

  6. Click the field under Type to define the type of data. Click the arrow and select Dynamic from the list and click OK to close the schema editor.

    Warning

    Under Type, the dynamic column type must be set as Dynamic.

  7. Next to the Table Name field, click the [...] button to select the database table of interest.

    A dialog box displays a tree diagram of all the tables in the selected database:

  8. Click the table of interest and then click OK to close the dialog box. Set the Query Type as Built-In.

  9. In the Query box, enter the query required to retrieve all of the columns from the table.

    Warning

    In the SELECT statement it is necessary to use the * wildcard character, to retrieve all of the columns from the selected table.

Configuring the tMap component

  1. Click tMap to open its Basic Settings view in the Component tab. Click [...] next to Map Editor to map the column from the source file.

  2. Drop the column defined as dynamic from the input schema on the left onto the output schema on the right.

    The column dropped on the output schema retains its original values.

    Warning

    The dynamic column must be mapped on a one to one basis and cannot undergo any transformations. It cannot be used in a filter expression or in a variables section. It cannot be renamed in the output table and cannot be used as a join condition.

  3. Click OK to close the Map Editor.

Configuring the output component

  1. Double-click tFileOutputDelimited to set its Basic Settings in the Component tab.

  2. Next to the File Name field, click the [...] button to browse your directory to where you want to save the output file, then enter a name for the file.

  3. Select the Include Header check box to retrieve the column names as well as the data.

Job execution

Save the Job and press F6 to run it.

The output file is written with all the column names and corresponding data, retrieved from the database via the dynamic schema:

Note

The Job can also be run in the Traces Debug mode, which allows you to view the rows as they are written to the output file, in the workspace.

For further information about defining and mapping dynamic schemas, see Talend Studio User Guide.

For related scenarios, see: