A column definitions file is a binary file which contains definitions for data grid columns. In other words, it contains a "skin" for table. Such files usually have .dcl extension.
To create a column definitions file after modifying the columns view, right-click the table and choose Save Columns.... To load a column definitions file, right-click the table and choose Load Columns.... It is also possible to load column definition files from command line.
Here is a table before and after loading column definitions file:
In order to avoid possible incompatibility errors when opening column definitions file in the application, please make sure the application major version is equal or larger than the version of the application, which created the file.