Use these options to add, remove, and edit custom data types. When you work with portable data types, you can use the default specifications or define a user-defined data type for easy reuse.
User-defined data types can save time and ensure consistency by providing a reusable data type that has a standard definition.
For example, you can create user-defined types whose names match those of your DBMS. You can then use data type names that correspond to those of your target DBMS, although DBMSs that have reserved words may not allow this.
You can also use user-defined types to create data types that are subsets of broader categories.
You can copy definitions from existing user-defined data types to new ones.
Note: Before you set data type information in your database model, you should be familiar with the data types and storage requirements supported by your target DBMS. Refer to the documentation for your target DBMS to determine which data type to assign.
User-defined types
Lists existing user-defined data types. Click the user-defined type that you want to remove, rename, or redefine.
Add
Click to open the Add New User-Defined Type dialog box, in which you can create a new user-defined type that has a default name and type definition.
You must name the new data type, and you must match it to a native portable data type used by Microsoft Office Visio.
Remove
Click to delete the selected user-defined type. If the type has been assigned to an object, a message appears asking whether to delete the user-defined type.
Rename
Click to open the Rename User-Defined Type dialog box and rename the selected user-defined type.
Category
Click a portable data type category available in Microsoft Office Visio.
Type
For the selected category, click an applicable type.
Some values for Type also require Size, Length, Precision, or Scale values.
Size
For the selected category and type, click a size.
Length
Type the number of characters.
Precision
Type the total number of digits (the number of digits to the left of the decimal point plus the number of digits to the right of the decimal point).
Scale
Type the number of digits to the right of the decimal point.
Description
Type text to describe the user-defined data type.
