Prerequisite Knowledge

Prerequisite Knowledge : Making changes to standard or existing functionality frequently involves making structural changes to tables that already contain data. These structural changes may include any of the following:

• Adding new fields
• Deleting existing fields
• Changing the data type or length of existing fields
• Changing other table or field properties, such as TableRelation or DataPerCompany

Client data is valuable. Making any structural changes to that data requires planning and accuracy. Microsoft Dynamics NAV 2013 safeguards the data by only allowing specific types of changes to tables that contain data. This prevents any accidental data loss, corruption, or other kinds of problems that can arise from modifications.

By understanding the kind of changes that you can make to existing tables, you can plan implementation and development activities.

Changing Tables that Contain Data

When you developed the Seminar Management functionality, you created several tables, and changed several existing ones. Microsoft Dynamics NAV Development Environment makes sure that no data is lost when you change the structure of a table. This means that when you  change a table that contains data, there are important guidelines that specify the changes that are allowed under certain conditions.

Changes to Fields

You can always make the following changes to table fields:

• Change the name.
• Change any properties that only control how data is displayed or formatted.
• Change the TableRelation, ValidateTableRelation, and TestTableRelation properties.
• Change a FlowField back to a regular field.
• Change the CalcFormula on a FlowField.
• Increase the length of a text or a code field.
• Add a new field.

You can make the following changes if the field does not contain data in any of the records for any companies in the database:

• Change the Data Type.
• Change the Field No.
• Change a normal field into a FlowField.
• Disable a field by setting Enabled to No.
• Delete the field.