For your use case of getting the column information before creating the base views from the data source, I would do the following steps to achieve it using the Graphical User Interface,
* Open the JDBC data source by double-clicking it in the **Server Explorer**.
* Click **Create base view**, the schemas of the database will be displayed.
* Click on any schema, to inspect its tables.
* The tables can be further expanded to view the column details.
Alternatively, I could also **create base view** on top of the JDBC data source using the “[Create from query](https://community.denodo.com/kb/en/view/document/Using%20the%20Create%20Base%20View%20From%20Query%20Option)” option in order to get the source column details in the table format,
* For example, to get the column details of the Microsoft SQL Server tables, I would use a similar SQL query for creating base view,
`SELECT TAB.NAME AS TABLE_NAME, TAB.OBJECT_ID AS OBJECT_ID, COL.NAME AS COLUMN_NAME, TYP.NAME AS DATA_TYPE_NAME, TYP.MAX_LENGTH AS MAX_LENGTH FROM SYS.COLUMNS COL INNER JOIN SYS.TABLES TAB ON COL.OBJECT_ID = TAB.OBJECT_ID INNER JOIN SYS.TYPES TYP ON TYP.USER_TYPE_ID = COL.USER_TYPE_ID`
Hope this helps!