Queries

Queries help you to find and list assets, their properties, and their relationships. A query is composed of its definition and its results.

Published queries are queries that any user can run. Alternatively, queries that you created and that only you can edit and run are called user queries. You can run either type of query on all catalog assets if you are in the Catalog tab, or on glossary assets if you are in the Development Glossary tab.

Each query is based on a single asset type, but you can define queries so that they primarily list the features of related assets. For example, you might base a query on the database asset type. But you might define the properties of the query to return detailed information about the database tables that are related to a single database.

Sharing query definitions

When you create a query, it is visible only to you. When you publish the query, other users can see and run it.

In the Manage Queries page, you can also export and import queries in a Workbench Query (WBQ) format so that users of other instances of IBM® InfoSphere® Information Governance Catalog can use your queries. The WBQ format is a proprietary format, which means that you can edit the query files only by using InfoSphere Information Governance Catalog.

Query results that are saved to a file

You can save query results in a comma-separated value (CSV) file or in a Microsoft Excel (XLS) file. Within any query result, at most 10,000 rows can be saved. InfoSphere Information Governance Catalog limits the number of rows that are saved for the following reasons:

CPU burden: Depending on how much information a query selects and how costly it is to retrieve it internally, it can take about one minute for every 1,000 rows of saved query results. Therefore, the row limit ensures that IBM InfoSphere Information Server resources are not consumed for too long. The row limit is enforced regardless of the format (CSV or XLS) of the file that the rows are saved to.
Microsoft Excel row limitations: In Microsoft Excel 97 for Windows, Microsoft Excel 2000, Microsoft Excel 2002, and Microsoft Office Excel 2003, text files that contain more than 65,536 rows cannot be opened in their entirety. Versions of Excel earlier than Excel 97 have a limit of 16,384 rows. Versions of Excel later than Excel 2003 have a limit of 1,048,576 rows. For details, see http://support.microsoft.com/kb/120596.
Memory limitations, in the case of XLS (Microsoft Excel) format: Saving to Microsoft Excel format requires that the whole spreadsheet document data structure is constructed in memory before serializing it. Therefore, you must consider memory resources when you increase the row limit.; Saving to CSV format does not have this scalability consideration. The spreadsheet data structure is serialized in chunks.

Query results with many relationships

Within any query result, at most 25 related assets are shown for each relationship. InfoSphere Information Governance Catalog limits the number of related assets per relationship that are displayed to ensure that this activity does not destabilize InfoSphere Information Server when invoking queries.

Queries to display data in asset details page in a tabular format

You can create a query to display data in tabular format in asset details page. For more information, see Displaying database column properties in a tabular format in the Database Table Details page technote.