Customizing the display of particular data types

Sometimes, you need to display particular columns using a certain column function. Examples:

Oracle Timestamps often need to be displayed with TO_CHAR(timestamp_col). If this is not done, the ODBC Driver can crash (depending on the version of the driver you are using).
SQL Server 2008 has datatypes HierarchyID, GeometryID and GeographyID. To display these, you need to use the ToString function, eg. geometry_column.ToString.
User-defined types, in particular object types, may have particular requirements for how they are displayed.

AQT provides a generic mechanism for dealing with columns such as this. This is done by coding a displaycol specification in the cfg file. Example:

displaycol;timestamp;to_char(:);
displaycol;geometry;:.ToString();

Note: where : appears, the column name will be substituted.

How this works

By default, when AQT displays a table, it builds a Default Query. In most cases this is:

select * from table

When a displaycol setting is used, the Default Query will be:

select col1, col2, to_char(timestamp_col) as timestamp_col from table

This will display the data using the function specified in the displaycol specifications (to_char in this example).

This default query will be used when you display a table, or go to the Run SQL or Query Builder windows. If you specify select * from table, the displaycol specification will not be used.

Other uses for Displaycol

This is a flexible option that can be used for a number of purposes.

To prevent the display of BLOB columns, code:

displaycol;blob;'BLOB data, not displayed';

To display only the first 1000 bytes of a CLOB column, code:

displaycol;clob;left(:,1000);

Advanced Query Tool

https://www.querytool.com