Setting schemas in the Map Editor

Talend Platform for Enterprise Integration Studio User Guide

EnrichVersion
5.6
EnrichProdName
Talend Platform for Enterprise Integration
task
Design and Development
Data Quality and Preparation
EnrichPlatform
Talend Studio

In the Map Editor, you can define the type of a table schema as Built-In so that you can modify the data structure in the Schema editor panel, or Repository and retrieve the data structure from the Repository. By default, the schema type is set to Built-In for all tables.

Retrieving the schema structure from the Repository

Warning

For Big Data users only:

This feature is not available in the Map/Reduce version of tMap.

To retrieve the schema structure of the selected table from the Repository:

  1. Click the tMap Settings button at the top of the table to display the table properties.

  2. Click in the Value field of Schema Type, and then click the three-dot button that appears to open the [Options] dialog box.

  3. In the [Options] dialog box, double-click Repository, or select it and click OK, to close the dialog box and display the Schema Id property beneath Schema Type.

    Note

    If you close the Map Editor now without specifying a Repository schema item, the schema type changes back to Built-In.

  4. Click in the Value field of Schema Id, and then click the [...] button that appears to display the [Repository Content] dialog box.

  5. In the [Repository Content] dialog box, select your schema as you define a centrally stored schema for any component, and then click OK.

    The Value field of Schema Id is filled with the schema you just selected, and everything in the Schema editor panel for this table becomes read-only.

    Note

    Changing the schema type of the subordinate table across a Join from Built-In to Repository causes the Join to get lost.

    Note

    Changes to the schema of a table made in the Map Editor are automatically synchronized to the schema of the corresponding component connected with the tMap component.

Using the Schema Editor

The Schema Editor details all fields of the selected table. With the schema type of the table set to Built-In, you can modify the schema of the table.

Use the tool bar below the schema table, to add, move or remove columns from the schema.

You can also load a schema from the repository or export it into a file.

Metadata

Description

Column

Column name as defined on the Map Editor schemas and on the Input or Output component schemas.

Key

The Key shows if the expression key data should be used to retrieve data through the Join link. If unchecked, the Join relation is disabled.

Type

Type of data: String, Integer, Date, etc.

Note

This column should always be defined in a Java version.

Length

-1 shows that no length value has been defined in the schema.

Precision

Defines the number of digits to the right of the decimal point.

Nullable

Clear this check box if the field value should not be null.

Default

Shows any default value that may be defined for this field.

Comment

Free text field. Enter any useful comment.

Note

Input metadata and output metadata are independent from each other. You can, for instance, change the label of a column on the output side without the column label of the input schema being changed.

However, any change made to the metadata are immediately reflected in the corresponding schema on the tMap relevant (Input or Output) area, but also on the schema defined for the component itself on the design workspace.

A Red colored background shows that an invalid character has been entered. Most special characters are prohibited in order for the Job to be able to interpret and use the text entered in the code. Authorized characters include lower-case, upper-case, figures except as start character.