tMysqlInput - 6.1

Talend Components Reference Guide

EnrichVersion
6.1
EnrichProdName
Talend Big Data
Talend Big Data Platform
Talend Data Fabric
Talend Data Integration
Talend Data Management Platform
Talend Data Services Platform
Talend ESB
Talend MDM Platform
Talend Open Studio for Big Data
Talend Open Studio for Data Integration
Talend Open Studio for Data Quality
Talend Open Studio for ESB
Talend Open Studio for MDM
Talend Real-Time Big Data Platform
task
Data Governance
Data Quality and Preparation
Design and Development
EnrichPlatform
Talend Studio

Function

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

Purpose

tMysqlInput 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.

If you have subscribed to one of the Talend solutions with Big Data, this component is available in the following types of Jobs:

tMysqlInput properties

Component family

Databases/MySQL

 

Basic settings

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

Repository: Select the repository file where the properties are stored.

 

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.

 

DB version

Select the version of the database to be used.

 

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 (columns) 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: 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:

  • 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

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.

  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.

Warning

If you use the component's own DB configuration, your data source connection will be closed at the end of the component. To prevent this from happening, use a shared DB connection with the data source alias specified.

This check box is not available when the Use an existing connection check box is 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&zeroDa­teTimeBehavior=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.

This check box is available only when Mysql 4 or Mysql 5 is selected from the DB Version drop-down list.

 

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

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 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 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 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.

Dragging and dropping components and linking them together

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

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

Configuring the components

  1. Double-click tMysqlInput 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.

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

    Click the field under Type to define the type of data.

    Click OK to close the schema editor.

  5. 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:

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

  7. Set the Query Type as Built-In.

  8. In the Query box, enter the query required to retrieve the desired columns from the table.

  9. Double-click tFileOutputDelimited to set its Basic settings in the Component tab.

  10. 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.

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

  11. Save the Job.

Executing the Job

The results below can be found after F6 is pressed to run the Job.

As shown above, 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: Using context parameters when reading a table from a MySQL database

In this scenario, we will read a table from a MySQL database, using a context parameter to refer to the table name.

Dragging and dropping components and linking them together

  1. Drop tMysqlInput and tLogRow from the Palette onto the workspace.

  2. Link tMysqlInput to tLogRow using a Row > Main connection.

Configuring the components

  1. Double-click tMysqlInput 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 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, seven columns in this example: id, first_name, last_name, city, state, date_of_birth and salary.

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

    Click the fields under Type to define the type of data.

    Click OK to close the schema editor.

  5. Put the cursor in the Table Name field and press F5 for context parameter setting.

    For more information about context settings, see Talend Studio User Guide.

  6. Keep the default setting in the Name field and type in the name of the database table in the Default value field, employees in this case.

  7. Click Finish to validate the setting.

    The context parameter context.TABLE automatically appears in the Table Name field.

  8. In the Query type list, select Built-In. Then, click Guess Query to get the query statement.

    In this use case, we want to read the records with the salary above 8000. Therefore, we add a Where clause and the final query statement is as follows:

    "SELECT 
      "+context.TABLE+".`id`, 
      "+context.TABLE+".`first_name`, 
      "+context.TABLE+".`last_name`, 
      "+context.TABLE+".`city`, 
      "+context.TABLE+".`state`, 
      "+context.TABLE+".`date_of_birth`, 
      "+context.TABLE+".`salary`
    FROM "+context.TABLE+"
    WHERE
      "+context.TABLE+".`salary` > 8000"
  9. Double-click tLogRow to set its Basic Settings in the Component tab.

  10. In the Mode area, select Table (print values in cells of a table) for a better display of the results.

  11. Save the Job.

Executing the Job

The results below can be found after F6 is pressed to run the Job.

As shown above, the records with the salary greater than 8000 are retrieved.

Scenario 3: Reading data from MySQL databases through context-based dynamic connections

In this scenario we will read data from database tables with the same data structure but in two different MySQL databases named project_q1 and project_q2 respectively. We will specify the connections to these databases dynamically at runtime, without making any modification to the Job.

Dropping and linking the components

  1. Drop two tMysqlConnection, a tMysqlInput, a tLogRow, and a tMysqlClose components onto the design workspace.

  2. Link the first tMysqlConnection to the second tMysqlConnection and the second tMysqlConnection to tMysqlInput using Trigger > On Subjob Ok connections.

  3. Link tMysqlInput to tLogRow using a Row > Main connection.

  4. Link tMysqlInput to tMysqlClose using a Trigger > On Subjob Ok connection.

Creating a context variable

To be able to choose a database connection dynamically at runtime, we need to define a context variable, which will then be configure it in the Dynamic settings of the database input component.

  1. In the Contexts view, click the [+] button to add a row in the table, click in the Name field and enter a name for the variable, myConnection in this example.

  2. From the Type list field, select List Of Value.

  3. Click in the Value field and then click the button that appears in the field to open the [Configure value of list] dialog box.

  4. In the [Configure value of list] dialog box, click the New... button to open the [New Value] dialog box, and enter the name of one of the connection components in the text field, tMysqlConnection_1 in this example. Then click OK to close the dialog box.

    Repeat this step to specify the other connection component name as another list item, tMysqlConnection_2 in this example.

    When done, click OK to close the [Configure Values] dialog box.

  5. Select the check box next to the variable value field, and fill the Prompt field with the message you want to display at runtime, Select a connection component: in this example.

Configuring the components

  1. Double-click the first tMysqlConnection component to show its Basic settings view, and set the connection details. For more information on the configuration of tMysqlConnection, see tMysqlConnection.

    Note that we use this component to open a connection to a MySQL databased named project_q1.

  2. Configure the second tMysqlConnection component in the same way, but fill the Database field with project_q2 because we want to use this component to open a connection to another MySQL database, project_q2.

  3. Double-click the tMysqlInput component to show its Basic settings view.

  4. Select the Use an existing connection check box, and leave the Component List box as it is.

  5. Click the [...] button next to Edit schema to open the [Schema] dialog box and define the data structure of the database table to read data from.

    In this example, the database table structure is made of four columns, id (type Integer, 2 characters long), firstName (type String, 15 characters long), lastName (type String, 15 characters long), and city (type String, 15 characters long). When done, click OK to close the dialog box and propagate the schema settings to the next component.

  6. Fill the Table field with the database table name, customers in this example, and click Guess Query to generate the query statement corresponding to your table schema in the Query field.

  7. In the Dynamic settings view, click the [+] button to add a row in the table, and fill the Code field with the code script of the context variable you just created, " + context.myConnection + " in this example.

  8. In the Basic settings view of the tLogRow component, select the Table option for better display effect of the Job execution result.

  9. In the Dynamic settings view of the tMysqlClose component, do exactly the same as in the Dynamic settings view of the tMysqlInput component.

Saving and executing the Job

  1. Press Ctrl+S to save your Job and press F6 or click Run to launch it.

    A dialog box appears prompting you to specify the connection component you want to use.

  2. Select the connection component, tMysqlConnection_1, and click OK.

    The data read from database project_q1 is displayed in the Run console.

  3. Press F6 or click Run to launch your Job again. When prompted, select the other connection component, tMysqlConnection_2, to read data from the other database, project_q2.

    The data read from database project_q2 is displayed in the Run console.

Scenario 4: 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.

Dragging and dropping components and linking them together

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

  2. Link tMysqlInput to tMap using a Row > Main connection.

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

Configuring the components

Data source and dynamic columns

  1. Double-click tMysqlInput 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.

    Next to Host, enter the database server IP address.

    Next to Port, enter the listening port number of the database server.

    Enter your authentication data in the Username and Password fields.

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

    The schema editor opens:

  4. Click the [+] button to add a row to the schema.

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

    Click the field under Type to define the type of data.

    Click the arrow and select Dynamic from the list.

    Warning

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

  5. Click OK to close the schema editor.

  6. 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:

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

  7. Set the Query Type as Built-In.

    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.

  8. Click tMap to open its Basic Settings view in the Component tab.

  9. Click [...] next to Map Editor to map the column from the source file.

  10. 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.

  11. Click OK to close the Map Editor.

Output file

  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.

  4. Save the Job.

Executing the Job

The results below can be found after F6 is pressed to run the Job.

As shown above, 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.

tMysqlInput properties in MapReduce Jobs

Component family

Databases/MySQL

 

Basic settings

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

Repository: Select the repository file where the properties are stored.

 

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.

 

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.

 

DB version

Select the version of the database to be used.

 

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 (columns) 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:

  • 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

Name of the table to be read.

 

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

Usage in Map/Reduce Jobs

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.

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.

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.

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.

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.

Related scenarios

No scenario is available for the Map/Reduce version of this component yet.

tMysqlInput properties in Spark Batch Jobs

Component family

Databases/MySQL

 

Basic settings

Property type

Either Built-In or Repository.

Built-In: No property data stored centrally.

Repository: Select the repository file where the properties are stored.

 

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.

 

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.

 

DB version

Select the version of the database to be used.

 

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 (columns) 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:

  • 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

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.

 Advanced settings

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

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

Usage in Spark Batch Jobs

In a Talend Spark Batch Job, it is used as a start component and requires an output link. The other components used along with it must be Spark Batch components, too. They generate native Spark code that can be executed directly in a Spark cluster.

This component should use a tMysqlConfiguration component present in the same Job to connect to MySQL. You need to select the Use an existing connection check box and then select the tMysqlConfiguration component to be used.

This component, along with the Spark Batch component Palette it belongs to, appears only when you are creating a Spark Batch Job.

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

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.

Spark Connection

You need to use the Spark Configuration tab in the Run view to define the connection to a given Spark cluster for the whole Job. In addition, since the Job expects its dependent jar files for execution, one and only one file system related component from the Storage family is required in the same Job so that Spark can use this component to connect to the file system to which the jar files dependent on the Job are transferred:

This connection is effective on a per-Job basis.

Related scenarios

No scenario is available for the Spark Batch version of this component yet.