August 15, 2023

tELTGreenplumMap – Docs for ESB 6.x

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tELTGreenplumMap

Uses the tables provided as input to feed the parameter in the built statement. The
statement can include inner or outer joins to be implemented between tables or between
one table and its aliases.

The three ELT Greenplum components are closely related, in terms of
their operating conditions. These components should be used to handle Greenplum DB
schemas to generate Insert statements, including clauses, which are to be executed in
the DB output table defined.

Helps you to build the SQL statement graphically, using the table
provided as input.

tELTGreenplumMap Standard properties

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

The Standard
tELTGreenplumMap component belongs to the ELT family.

The component in this framework is generally available.

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.

ELT Greenplum Map Editor

The ELT Map editor allows you to define the output schema and make a
graphical build of the SQL statement to be executed. The column names of
schema can be different from the column names in the database.

Style link

Select the way in which links are displayed.

Auto: By default, the links between the
input and output schemas and the Web service parameters are in the form
of curves.

Bezier curve: Links between the schema
and the Web service parameters are in the form of curve.

Line: Links between the schema and the
Web service parameters are in the form of straight lines.

This option slightly optimizes performance.

Property type

Either Built-in or Repository.

 

Built-in: No property data stored
centrally.

 

Repository: Select the Repository
file where Properties are stored. The following fields are pre-filled in
using fetched data.

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.

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.

tStatCatcher Statistics

Select this check box to gather the Job processing metadata at a Job
level as well as at each component level.

Global Variables

Global Variables

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

tELTGreenplumMap is used along with
tELTGreenplumInput and tELTGreenplumOutput. Note that the Output
link to be used with these components must correspond strictly to the
syntax of the table name.

Note:

Note that the ELT components do not handle actual data flow but
only schema information.

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.

Scenario: Mapping data using a simple implicit join

In this scenario, a tELTGreenplumMap component is
deployed to retrieve the data from the source table employee_by_statecode, compares its statecode column against the table statecode, and then maps the desired columns from the two tables to the
output table employee_by_state.

Before the Job execution, the three tables, employee_by_statecode, statecode and
employee_by_state look like:

use_case_teltgreenplummap_2.png

Dropping components

  1. Drop tGreenplumConnection, tELTGreenplumInput (two), tELTGreenplumMap, tELTGreenplumOutput, tGreenplumCommit, tGreenplumInput and tLogRow
    from the Palette onto the workspace.
  2. Rename tGreenplumConnection as connect_to_greenplum_host, two tELTGreenplumInput components as employee+statecode and statecode, tELTGreenplumMap as
    match+map, tELTGreenplumOutput as map_data_output, tGreenplumCommit as commit_to_host, tGreenplumInput
    as read_map_output_table and tLogRow as show_map_data.
  3. Link tGreenplumConnection to tELTGreenplumMap using an OnSubjobOk trigger.

    Link tELTGreenplumMap to tGreenplumCommit using an OnSubjobOk trigger.
    Link tGreenplumCommit to tGreenplumInput using an OnSubjobOk trigger.
  4. Link tGreenplumInput to tLogRow using a Row > Main
    connection.

    The two tELTGreenplumInput components and
    tELTGreenplumOutput will be linked to
    tELTGreenplumMap later once the relevant
    tables have been defined.
    use_case_teltgreenplummap_1.png

Configuring the components

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

    use_case_teltgreenplummap_3.png

    In the Host and Port fields, enter the context variables for the Greenplum
    server.
    In the Database field, enter the context
    variable for the Greenplum database.
    In the Username and Password fields, enter the context variables for the
    authentication credentials.
    For more information on context variables, see
    Talend Studio User
    Guide    .
  2. Double-click employee+statecode to open its
    Basic settings view in the Component tab.

    use_case_teltgreenplummap_4.png

    In the Default table name field, enter the
    name of the source table, namely employee_by_statecode.
    Click the […] button next to the Edit schema field to open the schema editor.
    use_case_teltgreenplummap_5.png

    Click the [+] button to add three columns,
    namely id, name and
    statecode, with the data type as INT4, VARCHAR,
    and INT4 respectively.
    Click OK to close the schema editor.
    Link employee+statecode to tELTGreenplumMap using the output employee_by_statecode.
  3. Double-click statecode to open its Basic settings view in the Component tab.

    use_case_teltgreenplummap_6.png

    In the Default table name field, enter the
    name of the lookup table, namely statecode.
  4. Click the […] button next to the Edit schema field to open the schema editor.

    use_case_teltgreenplummap_7.png

    Click the [+] button to add two columns,
    namely state and
    statecode, with the data type as VARCHAR and INT4
    respectively.
    Click OK to close the schema editor.
    Link statecode to tELTGreenplumMap using the output statecode.
  5. Click tELTGreenplumMap to open its Basic settings view in the Component tab.

    use_case_teltgreenplummap_10.png

    Select the Use an existing connection check
    box.
  6. Click the […] button next to the ELT Greenplum Map Editor field to open the map
    editor.

    use_case_teltgreenplummap_11.png

  7. Click the [+] button on the upper left corner
    to open the table selection box.

    use_case_teltgreenplummap_12.png

    Select tables employee_by_statecode and
    statecode in sequence and click Ok.
    The tables appear on the left panel of the editor.
  8. On the upper right corner, click the [+]
    button to add an output table, namely employee_by_state.

    Click Ok to close the map editor.
  9. Double-click tELTGreenplumOutput to open its
    Basic settings view in the Component tab.

    use_case_teltgreenplummap_8.png

    In the Default table name field, enter the
    name of the output table, namely employee_by_state.
  10. Click the […] button next to the Edit schema field to open the schema editor.

    use_case_teltgreenplummap_9.png

    Click the [+] button to add three columns,
    namely id, name and
    state, with the data type as INT4, VARCHAR, and VARCHAR respectively.
    Click OK to close the schema editor.
    Link tELTGreenplumMap to tELTGreenplumOutput using the table output employee_by_state.
    Click OK on the pop-up window below to
    retrieve the schema of tELTGreenplumOutput.
    use_case_teltgreenplummap_14.png

    Now the map editor’s output table employee_by_state shares the same schema as that of tELTGreenplumOutput.
  11. Double-click tELTGreenplumMap to open the map
    editor.

    Drop the column statecode from table
    employee_by_statecode to its counterpart
    of the table statecode, looking for the
    records in the two tables that have the same statecode values.
    Drop the columns id and name from table employee_by_statecode as well as the column statecode from table statecode to their counterparts in the output table employee_by_state.
    Click Ok to close the map editor.
  12. Double-click tGreenplumInput to open its
    Basic settings view in the Component tab.

    use_case_teltgreenplummap_16.png

    Select the Use an existing connection check
    box.
    In the Table name field, enter the name of
    the source table, namely employee_by_state.
    In the Query field, enter the query
    statement, namely "SELECT * FROM "employee_by_state"".
  13. Double-click tLogRow to open its Basic settings view in the Component tab.

    use_case_teltgreenplummap_17.png

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

Executing the Job

  1. Press Ctrl+S to save the Job.
  2. Press F6 to run the Job.

    use_case_teltgreenplummap_18.png

    As shown above, the desired employee records have been written to the table
    employee_by_state, presenting clearer
    geographical information about the employees.
Document get from Talend https://help.talend.com
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Docs 6.x
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