Joining virtual objects (Data Virtualization)

You can join multiple tables from multiple data sources into a single virtual table, which is also known as a join view.

About this task

To create a virtual view from existing virtualized tables, complete the following steps.

Procedure

  1. Click Data > Data Virtualization. From the Virtualization menu, click My virtualized data. Your existing virtualized tables are listed.
    Tip: If you prefer, you can click Open in SQL editor to skip the following steps and use the IBM common SQL engine instead. See the SQL Reference for more details on SQL syntax and function compatibility.
  2. Select the tables that you want to join and click Join to display the Join virtual objects window.
  3. If you selected two tables, you can use the graphical join wizard to click and drag from one column name to another to create a join key. The join keys must be of the same data type. This step does not copy or move any data. It creates a table definition that is a combination of the two tables.
    Joining two tables
    Restriction: If you are joining tables with many rows, the preview of the join might time out after 10 minutes if the data sources are unable to complete the processing of the join.

    If you selected more than two tables, you are taken to the SQL editor, which is pre-populated with a CREATE VIEW statement referencing the selected tables. You need to modify this statement to add join predicate, filters, and any functions needed. See the SQL Reference for a full description of the supported operations.

  4. Click Next. You can use the new table to query the data from both of the base tables.
  5. On the Edit column names screen, enter a View name, select a Schema, and edit column names as needed.
  6. Select where to assign the view to one of three options:
    Assign to When to use this option
    Project Select Project if you created the virtual table to use in a specific analytics project. Then, choose the appropriate project.
    My virtualized data Select My virtualized data if the table was not created to use in a specific project. This is the default setting if no projects exist.
  7. Click Create view to complete the process.

What to do next

You can use the virtualized data in a number of different ways. For example, you can use them in a Jupyter Notebook, create new models within the Model Builder, or build charts or graphics on the analytics dashboard.
Note: You cannot apply data masking policies with views. For more information, see Restrictions for data masking.