August 15, 2023

tELTTeradataMap – Docs for ESB 6.x

tELTTeradataMap

Builds the SQL SELECT statement using the table schema(s) provided by one or more
tELTTeradataInput components.

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

tELTTeradataMap Standard properties

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

The Standard
tELTTeradataMap 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 Teradata Map editor

The ELT Map editor allows you to define the output schema as well as
build graphically 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

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

Query band

Select this check box to use the Teradata Query Banding feature to add metadata to the query
to be processed, such as the user running the query. This can help you, for example,
identify the origin of this query.

Once selecting the check box, the Query Band parameters
table is displayed, in which you need to enter the metadata information to be added. This
information takes the form of key/value pairs, for example, DpID in the Key column and Finance in the Value
column.

This check box actually generates the SET QUERY_BAND FOR SESSION statement with the key/value
pairs declared in the Query Band parameters table. For
further information about this statement, see http://www.info.teradata.com/HTMLPubs/DB_TTU_14_00/index.html#page/SQL_Reference/B035_1144_111A/End_Logging-Syntax.027.143.html.

This check box is not available when you have selected the Using an
existing connection
check box. In this situation, if you need to use the
Query Band feature, set it in the Advanced settings tab of
the Teradata connection component to be used.

tStatCatcher Statistics

Select this check box to collect log data at the 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

tELTTeradataMap is used along with a
tELTTeradataInput and tELTTeradataOutput. Note that the Output link
to be used with these components must faithfully reflect the name of the
tables.

Note:

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 subquery

This scenario describes a Job that maps the data from two input tables PreferredSubject and CourseScore to the output table TotalScoreOfPreferredSubject using a subquery.

components-teltteradatamap_s1_job.png
The PreferredSubject table contains the student’s
preferred subject data. To reproduce this scenario, you can load the data to the table from
a CSV file like the following. For how to load data to a Teradata table, see Scenario: Loading data into a Teradata database.
The CourseScore table contains the student’s subject
score data. To reproduce this scenario, you can load the data to the table from a CSV file
like the following. For how to load data to a Teradata table, see Scenario: Loading data into a Teradata database.
Before the Job execution, there is no data in the output table TotalScoreOfPreferredSubject:

Dropping and renaming the components

  1. Create a new Job and add the following components by typing their names in the
    design workspace or dropping them from the Palette: two tELTTeradataInput
    components, two tELTTeradataMap components, and
    one tELTTeradataOutput component.
  2. Rename two tELTTeradataInput components to
    PreferredSubject and CourseScore respectively, two tELTTeradataMap components to ELTSubqueryMap and ELTMap
    respectively, and the tELTTeradataOutput
    component to TotalScoreOfPreferredSubject.

Configuring the input components

  1. Double-click PreferredSubject to open its
    Basic settings view.

    components-teltteradatamap_s1_preferredsubject.png

  2. In the Default Table Name field, enter an
    input table name. In this example, it is PreferredSubject.
  3. Click the […] button next to Edit schema to define the schema of the input table
    PreferredSubject in the schema
    editor.

    components-teltteradatamap_s1_preferredsubject_schema.png

    Click the [+] button to add four columns,
    SeqID with the DB Type set to INTEGER, StuName,
    Subject, and Detail with the DB Type set to VARCHAR.
    Click OK to validate these changes and close
    the schema editor.
  4. Connect PreferredSubject to ELTMap using the Link > PreferredSubject
    (Table)
    link.
  5. Double-click CourseScore to open its
    Basic settings view.

    components-teltteradatamap_s1_coursescore.png

  6. In the Default Table Name field, enter an
    input table name. In this example, it is CourseScore.
  7. Click the […] button next to Edit schema to define the schema of the input table
    CourseScore in the schema editor.

    components-teltteradatamap_s1_coursescore_schema.png

    Click the [+] button to add six columns,
    SeqID and Score with the DB Type set to INTEGER, StuName, Subject, Course
    and Detail with the DB Type set to VARCHAR.
    Click OK to validate these changes and close
    the schema editor.
  8. Connect CourseScore to ELTSubqueryMap using the Link > CourseScore (Table)
    link.

Configuring the output component

  1. Double-click TotalScoreOfPreferredSubject
    to open its Basic settings view.

    components-teltteradatamap_s1_totalscore.png

  2. In the Default Table Name field, enter an
    output table name. In this example, it is TotalScoreOfPreferredSubject.
  3. Click the […] button next to Edit schema to define the schema of the output table
    in the schema editor.

    components-teltteradatamap_s1_totalscore_schema.png

    Click the [+] button to add four columns,
    SeqID and TotalScore with the DB Type set to INTEGER, StuName and
    PreferredSubject with the DB Type set to
    VARCHAR.
    Click OK to validate these changes and close
    the schema editor.

Configuring data mapping to generate a subquery

  1. Click ELTSubqueryMap to open its Basic settings view.

    components-teltteradatamap_s1_eltsubquerymap.png

    Note that you do not need to specify the Teradata database connection
    information in the ELTSubqueryMap component.
    The connection information will be specified in the ELTMap component.
  2. Click the […] button next to ELT Teradata Map Editor to open its map
    editor.

    components-teltteradatamap_s1_eltsubquerymap_mapeditor.png

  3. Add the input table CourseScore by clicking
    the [+] button in the upper left corner of the
    map editor and then selecting the relevant table name from the drop-down list in
    the pop-up dialog box.
  4. Add an output table by clicking the [+]
    button in the upper right corner of the map editor and then entering the table
    name TotalScore in the corresponding field in
    the pop-up dialog box.
  5. Drag StuName, Subject, and Score columns in
    the input table and then drop them to the output table.
  6. Click the Add filter row button in the upper
    right corner of the output table and select Add an
    other(GROUP…) clause
    from the pop-up menu. Then in the
    Additional other clauses (GROUP/ORDER
    BY…)
    field displayed, enter the clause GROUP BY CourseScore.StuName, CourseScore.Subject.

    Add the aggregate function SUM for the column Score of the output table by changing the expression of this
    column to SUM(CourseScore.Score).
  7. Click the Generated SQL Select query for “table1”
    output
    tab at the bottom of the map editor to display the
    corresponding generated SQL statement.

    components-teltteradatamap_s1_eltsubquerymap_sql.png

    This SQL query will appear as a subquery in the SQL query generated by the
    ELTMap component.
  8. Click OK to validate these changes and close
    the map editor.
  9. Connect ELTSubqueryMap to ELTMap using the Link > TotalScore (table1)
    link. Note that the link is renamed automatically to TotalScore (Table_ref) since the output table TotalScore here is a reference table.

Mapping the input and output schemas

  1. Right-click ELTMap, select Link > *New Output*
    (Table)
    from the contextual menu and click TotalScoreOfPreferredSubject. In the pop-up dialog
    box, click Yes to get the schema from the
    target component.
  2. Click ELTMap to open its Basic settings view.

    components-teltteradatamap_s1_eltmap.png

    Fill in the Host, Database, Username, and
    Password fields with the Teradata database
    connection information.
  3. Click the […] button next to ELT Teradata Map Editor to open its map
    editor.

    components-teltteradatamap_s1_eltmap_mapeditor.png

  4. Add the input table PreferredSubject by
    clicking the [+] button in the upper left
    corner of the map editor and selecting the relevant table name from the
    drop-down list in the pop-up dialog box.

    Do the same to add another input table TotalScore.
  5. Drag the StuName column in the input table
    PreferredSubject and drop it to the
    corresponding column in the input table TotalScore. Then select the Explicit
    join
    check box for the StuName
    column in the input table TotalScore.

    Do the same for the Subject column.
  6. Drag the SeqID column in the input table
    PreferredSubject and drop it to the
    corresponding column in the output table.

    Do the same to drag the StuName and
    Subject columns in the input table
    PreferredSubject and the Score column in the input table TotalScore and drop them to the corresponding
    column in the output table.
  7. Click the Generated SQL Select query for “table2”
    output
    tab at the bottom of the map editor to display the
    corresponding generated SQL statement.

    components-teltteradatamap_s1_eltmap_sql.png

    The SQL query generated in the ELTSubqueryMap component appears as a subquery in the SQL query
    generated by this component. Alias will be automatically added for the selected
    columns in the subquery.
  8. Click OK to validate these changes and close
    the map editor.

Executing the Job

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

    components-teltteradatamap_s1_result.png

    components-teltteradatamap_s1_resultdata.png

    The select statement is generated and the mapping data are written into the
    output table.

Document get from Talend https://help.talend.com
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