tRedshiftInput

Reads data from a database and extracts fields based on a query so that you may
apply changes to the extracted data.

tRedshiftInput 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
through a Main row link.

Depending on the Talend solution you
are using, this component can be used in one, some or all of the following Job
frameworks:

Standard: see tRedshiftInput Standard properties.

The component in this framework is generally available.
Spark Batch: see tRedshiftInput properties for Apache Spark Batch.

The component in this framework is available only if you have subscribed to one
of the
Talend
solutions with Big Data.

tRedshiftInput Standard properties

These properties are used to configure tRedshiftInput running in the Standard Job framework.

The Standard
tRedshiftInput component belongs to the Cloud and the Databases families.

The component in this framework is generally available.

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.
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: 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. 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	Hostname or IP address of the database server.
Port	Listening port number of the database server.
Database	Name of the database.
Schema	Exact name of the schema.
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.
Additional JDBC Parameters	Specify additional JDBC properties for the connection you are creating. The properties are separated by ampersand & and each property is a key-value pair. For example, ssl=true & sslfactory=com.amazon.redshift.ssl.NonValidatingFactory, which means the connection will be created using SSL.
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 from which the data will be read.
Query Type and Query	Enter your database query paying particularly attention to sequence the fields properly in order to match the schema definition. If using the dynamic schema feature, the SELECT query must include the * wildcard, to retrieve all of the columns from the table selected.
Guess Query	Click the Guess Query button to generate the query which corresponds to your table schema in the Query field.
Guess schema	Click the Guess schema button to retrieve the table schema.

Advanced settings

Log file	Specify the path to the log file to be generated during the data retrieval process. Note that if the logging information needs to be saved and this component reuses the connection created by a tRedshiftConnection component, you must specify the property loglevel=1/2/3 in the Additional JDBC Parameters field of the tRedshiftConnection component.
Logging level	Select a logging level from the drop-down list to specify which kind of events will be logged in the log file.
Use cursor	Select this check box to help 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.
tStatCatcher Statistics	Select this check box to collect log data at the component level.

Global Variables

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

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

QUERY: the 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

Usage rule	This component covers all possible SQL queries for Amazon Redshift databases.
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: Reading data from 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.
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. You can find more details about how to install external modules in Talend Help Center (https://help.talend.com).

Usage rule

This component covers all possible SQL queries for Amazon Redshift
databases.

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: Reading data from 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.

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. You can find more details about how to install external modules in Talend Help Center (https://help.talend.com).

Scenario: Handling data with Redshift

This scenario describes a Job that writes the personal information into Redshift, then
retrieves the information in Redshift and displays it on the console.

The scenario requires the following six components:

tRedshiftConnection: opens a connection to
Redshift.
tFixedFlowInput: defines the personal
information data structure, and sends the data to the next component.
tRedshiftOutput: writes the data it receives
from the preceding component into Redshift.
tRedshiftInput: reads the data from
Redshift.
tLogRow: displays the data it receives from
the preceding component on the console.
tRedshiftClose: closes the connection to
Redshift.

Dropping and linking the components

Drop the six components listed previously from the Palette onto the design workspace.
Connect tFixedFlowInput to tRedshiftOutput using a Row > Main
connection.
Connect tRedshiftInput to tLogRow also using a Row > Main
connection.
Connect tRedshiftConnection to tFixedFlowInput using a Trigger > OnSubjobOk
connection.
Connect tFixedFlowInput to tRedshiftInput and tRedshiftInput to tRedshiftClose also using a Trigger > OnSubjobOk
connection.

Configuring the components

Opening a connection to Redshift

Double-click tRedshiftConnection to open
its Basic settings view.
Select Built-In from the Property Type drop-down list.

In the Host, Port, Database, Schema, Username, and Password fields,
enter the information required for the connection to Redshift.
In Advanced settings view, select
Auto Commit check box to commit any
changes to Redshift upon each transaction.

Defining the input data

Double-click tFixedFlowInput to open its
Basic settings view.
Click the […] button next to Edit schema to open the schema editor.
In the schema editor, click the [+]
button to add three columns: id of the
interger type, name of the string type,
and age of the integer type.
Click OK to validate the changes and
accept the propagation prompted by the pop-up [Propagate] dialog box.
In the Mode area, select Use Inline Content (delimited file) and enter the
following personal information in the Content field.

1;Arthur;16 2;Ford;18 3;Jackson;17

1
2
3

1;Arthur;16
2;Ford;18
3;Jackson;17

Writing the data into Redshift

Double-click tRedshiftOutput to open its
Basic settings view.
Select the Use an existing connection
check box, and then select the connection you have already configured for
tRedshiftConnection from the Component List drop-down list.
In the Table field, enter or browse to
the table into which you want to write the data, redshiftexample in this scenario.
Select Drop table if exists and create
from the Action on table drop-down list,
and select Insert from the Action on data drop-down list.
Click Sync columns to retrieve the schema
from the preceding component tFixedFlowInput.

Retrieving the data from Redshift

Double-click tRedshiftInput to open its
Basic settings view.
Select the Use an existing connection
check box, and then select the connection you have already configured for
tRedshiftConnection from the Component List drop-down list.
Click the […] button next to Edit schema to open the schema editor.
In the schema editor, click the [+]
button to add three columns: id of the
interger type, name of the string type,
and age of the integer type. The data
structure is same as the structure you have defined for tFixedFlowInput.
Click OK to validate the changes and
accept the propagation prompted by the pop-up [Propagate] dialog box.
In the Table Name field, enter or browse
to the table into which you write the data, redshiftexample in this scenario.
Click the Guess Query button to generate
the query. The Query field will be filled
with the automatically generated query.

Displaying the defined information

Double-click tLogRow to open its
Basic settings view.
In the Mode area, select Table (print values in cells of a table) for a
better view of the results.

Closing the connection to Redshift

Double-click tRedshiftClose to open its
Basic settings view.
From Component List, select the
connection you have already configured for tRedshiftConnection.

Saving and executing the Job

Press Ctrl+S to save the Job.
Press F6 to execute the Job.

The personal information is written to the specified target Redshift
database, and then the data is retrieved from the database and displayed on
the console.