Retrieving schemas - 7.1

Talend Big Data Studio User Guide

author
Talend Documentation Team
EnrichVersion
7.1
EnrichProdName
Talend Big Data
task
Design and Development
EnrichPlatform
Talend Studio

About this task

In this step, we will retrieve the schemas of interest from the connected Cassandra database.

Procedure

  1. In the Repository view, right-click the newly created connection and select Retrieve Schema from the contextual menu.
    The wizard opens a new view that lists all the available column families of the specified keyspace, or all the available keyspaces if you did not specify one in the previous step.
  2. Expand the keyspace, or keyspaces of interest if you did not specify a keyspace in the previous step as in this example, and select the column family or column families of interest.
  3. Click Next to proceed to the next step of the wizard where you can edit the generated schema or schemas.
    By default, each generated schema is named after the column family on which it is based.
    Select a schema from the Schema panel to display its details on the right side, and modify the schema if needed. You can rename any schema, and customize the schema structure according to your needs in the Schema area.
    The tool bar allows you to add, remove or move columns in your schema, or replace the schema with the schema defined in an XML file.
    To base a schema on another column family, select the schema name in the Schema panel, and select a new column family from the Based on Column Family list, and click the Guess Schema button to overwrite the schema with that of the selected column family. You may need to click the refresh button to refresh the list of column families.
    To add a new schema, click the Add Schema button in the Schema panel, which creates an empty schema for you to define.
    To remove a schema, select the schema name in the Schema panel and click the Remove Schema button.
    To overwrite the modifications you made on the selected schema using its default schema, click Guess schema. Note that all your changes to the schema will be lost if you click this button.
  4. Click Finish to complete the schema creation. The result schemas appear under your Cassandra connection in the Repository view. You can now drop the connection or any schema node under it onto your design workspace as a Cassandra component, with all the metadata information automatically filled.
    If you need to further edit a schema, right-click the schema and select Edit Schema from the contextual menu to open this wizard again and make your modifications.
    Warning:

    If you modify the schemas, ensure that the data type in the Type column is correctly defined.