FAQs

In short a Row Type is a the design of a table.

Whenever you create a table you must either re-use an existing Row Type or create a new one and give it a name. By default the interface assumes that you are creating a new Row type and gives it the name of the table with the 's' removed from the end if there is one.

For example if you create a table called 'Rooms' the system will create a new row type called 'Room'.

This system falls down for a table called 'People' but you can edit the row name to be anything you want.

A row type contains the list of column names and data types for the table. When you add a column to a table you are adding a column to the Row type.

The reason we bother with the whole concept of Row Types is that it gives us a way to refer to the design of a table so that it can be reused and also so that it can be referred to in calculations.

A table has a row type for three specific reasons.

- So that a reference can specify the kind of row it is allowed to refer to.

- So that tables can share the same design. If I have a Row Type called 'Issue' which was created for a table of Issues in a 'Project', I might want to re-use it to add a list of issues to each task in the project. That way I can have one list of issues for each task and one list of issues for the project as a whole.

Adding or removing a column from any Issue table will now cause that same action to be performed on all tables with that row type which saves making the same change in multiple places.

- So that in calculations we can distinguish the designs of different rows and refer to them in different drop downs. This is especially relevant in parent pseudo columns which are created with the name of the parent row type.

A template contains

- All the user defined Row Types
- All the global views
- All the user defined enumeration types.

This is done by adding a column/paragraph of type 'Reference' to a table/page.
You will have to specify the Row Type of the row referred to by the reference but this is easily done via a drop down.

It is usually very useful to format a reference with an expression specifying all the rows that can be put in the reference. This allows the user to enter a reference using a drop down menu rather than having to browse the whole database for the reference they are interested in.

A drop down menu is added via the format tab of the Column Properties Dialog. This can be done when a column is created or at any time afterwards.

The format tab for a reference allows the user to enter an expression which returns a list of rows of the type being referenced. This may seem complicated but if you actually do it the graphic expression editor makes it very easy.

In most cases a reference can be loaded with the contents of a single table - often in the 'Home' page. The expression editor makes it very easy to enter these values.