Destructive and nondestructive changes

During a regular, upgrade type of installation of a clinical data model, if there have been destructive changes to any table, all data in that table is deleted.

Destructive changes include:

• Removing a column.

• Decreasing the length of a column.

• Changing the processing type.

• Changing the CREATE_AS_VIEW flag.

• Changing the tablespace name.

• Changing the primary key.

• Changing the "allow duplicate rows" setting.

Nondestructive changes include:

• Increasing the length of a column.

• Changing the data type of a column from number or date to character.

• Changing the Blinding attribute of a table from Yes to No or No to Yes.

• Changes to a table's Support Duplicate attribute from Yes to No or No to Yes.

• Adding a unique constraint.