August 17, 2023

tELTTeradataMap – Docs for ESB 5.x

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tELTTeradataMap

tELTTeradataMap_icon32.png

tELTTeradataMap properties

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

Component family

ELT/Map/Teradata

  

Function

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

Purpose

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.

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.

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 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.

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 more information on Dynamic settings and context
variables, see Talend Studio User Guide.

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

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.

Connecting ELT components

For detailed information regarding ELT component connections, see Connecting ELT components.

Related topic: see Talend Studio User
Guide.

Mapping and joining tables

In the ELT Mapper, you can select specific columns from input schemas and include
them in the output schema.

For detailed information regarding the table schema mapping and joining, see Mapping and joining tables.

Adding where and other clauses

You can also restrict the Select statement based on a Where clause and/or other clauses such
as Group By, Order By, etc. by clicking the Add filter
row button at the top of the output table in the map editor.

To add a restriction based on a Where clause, click the Add
filter row button and select Add a WHERE
clause from the popup menu.

To add a restriction based on Group By, Order By etc., click the Add filter row button and select Add an
other(GROUP…) clause from the popup menu.

components-teltmysqlmap_add_clauses.png

Make sure that all input components are linked correctly to the ELT Map component to
be able to implement all inclusions, joins and clauses.

Generating the SQL statement

The mapping of elements from the input schemas to the output schemas create
instantly the corresponding Select statement.

The clause defined internally in the ELT Mapper are also included
automatically.

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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