Redesigning a table

After you have designed your table and started to use it, that is to say, entered data in the fields, it is possible to change your design without having to start from the beginning. To change the structure of a database table – that is, to add, delete, redefine or reformat fields – do the following:

The "Format Table" dialog is opened. This dialog should be familiar to you from when you first designed the table, although it was then called "New Table".

In the Table Fields box, in "Format table", you will see all the fields from the table, along with their associated Name, Type, Description. To go to the Table Indexes box, where all the indexes for the table are displayed, click on the Index button.

There are several things you might want to do when redesigning a table:

  1. To delete a field completely (equivalent to deleting a column in the table), click on the left-hand row bar in Table Fields to select the field. Next, press Del on the keyboard and the selected field will be deleted. Several fields can be deleted at once, by dragging your mouse to select the relevant fields and then pressing Del. Be careful here: when a field is deleted the corresponding column in the table is deleted, along with all its data. So make sure you really no longer need this data, before deleting the field.

  2. To add a field, go to the next empty line and create the field in the normal way (see Creating fields in a database).

  3. To rename a field, just type the new name in Name.

  4. To change the data type of a field, click on the arrow in Type and select a different type from the drop down list.

  1. When you change the data type of a field, you will usually want to format the field anew, or you may wish to reformat a field even though you have not changed the data type. The formatting properties include width, validation, initial value, caption, primary key and indexes, etc. depending on the data type of the field. To reformat a field, make sure you are somewhere in the field and then click on the Format button (see Data types for information on the various data types and their respective formatting options).

  2. To change or add a description of the field, type the new description in Description.

  3. If you think the redesigned table merits a different description, then type this in the Table Description box.

  4. Once you have redesigned the table, click on OK to save it and return to Table Grid View. The table will be redrawn to reflect your changes and you can continue to enter data.