In this step, we will retrieve the table schema of interest from the connected HBase database.
In the Repository view, right-click the newly
created connection and select Retrieve schema
from the contextual menu, and click Next on the
wizard that opens to view and filter different tables in the HBase
You can define the number of columns to be displayed for each column family in the Limit field.If you want to set this limit for all the HBase/MapR-DB connection metadata to be defined in the Repository, set the limit in the HBase/MapR-DB scan limit field in Preferences > Talend > Performance.
Expand the relevant database table and column family nodes and select the
columns of interest, and click Next to open a
new view on the wizard that lists the selected table schema(s). You can select
any of them to display its details in the Schema area on the right side of the wizard.
Warning: If your source database table contains any default value that is a function or an expression rather than a string, be sure to remove the single quotation marks, if any, enclosing the default value in the end schema to avoid unexpected results when creating database tables using this schema. For more information, see Verifying default values in a retrieved schema.
Modify the selected schema if needed. You can rename the 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.To overwrite the modifications you made on the selected schema using its default schema, click Retrieve schema. Note that all your changes to the schema will be lost if you click this button.
Click Finish to complete the HBase table
schema creation. All the retrieved schemas are displayed under the related HBase
connection in the Repository view.
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.
if you select from the Hadoop cluster list the Repository option to reuse details of an established Hadoop connection, the created HBase connection will eventually be classified under both the Hadoop cluster node and the Db connection node;
otherwise, if you select from the Hadoop cluster list the None option in order to enter the Hadoop connection properties yourself, the created HBase connection will appear under the Db connection node only.