Columns (PDM)

A column contains an individual data item within a row. It is the model equivalent of a database column. A column is always defined for a table. When you create a column, it must be assigned a name and code. You can also select a data type for the column. This can be done directly from a list of available data types, or by attaching the column to a domain.

• Creating a Column
  You can create a column from the property sheet of, or in the Browser under, a table.
• Column Properties
  To view or edit a column's properties, double-click its Browser or list entry. The property sheet tabs and fields listed here are those available by default, before any customization of the interface by you or an administrator.
• Obtaining Column Statistics from your Database
  You can enter values in the Null values, Distinct values and Average length fields on the Detail tab on your column property sheets, or obtain appropriate values from your database.
• Setting Data Profiling Constraints
  PowerDesigner allows you to define data profiling constraints to control the range and format of data allowed in your database. You can specify constraints on the Standard Checks and Additional Checks tabs of table columns in your PDM, entity attributes in your CDM or LDM, and domains. You can also specify data quality rules on the Rules tab of PDM tables and columns, CDM/LDM entities and attributes, and domains.
• Populating Columns with Test Data
  You can use test data to quickly fill your database with large amounts of data in order to test its performance, and estimate its size. You can also use test data as the basis for data profiling. PowerDesigner allows you to create test data profiles, which generate or provide lists of data items and are assigned to columns or domains. You can create test data profiles that contain number, character, or date/time data.
• Creating a Computed Column
  A computed column is a column whose content is computed from values in other columns in the table. Computed columns are not available in all DBMSs.
• Selecting a Data Type for a Column
  There are two ways to select a data type for a column:
• Attaching a Column to a Domain
  If you attach a column to a domain, the domain supplies the data type and related data characteristics. It may also indicate check parameters, and business rules.
• Copying a Column to Another Table
  You can copy a column from one table and add it to another table. If the table already contains a column with the same name or code as the copied column, the copied column is renamed.
• Naming a Column Constraint
  A column constraint is a named check that enforces data requirements of check parameters.