A Developer’s Guide to SQL Server 2005

5. User-Defined Types and Aggregates

SQL SERVER PROVIDES types for scalars like FLOAT and CHAR. These can be represented by a single value, such as a number or a string. Some scalars, such as a date, require more than one value to be represented. A date has a month, day, and year value in its representation. SQL Server provides the DATETIME scalar type for dates. There are other scalars that require more than one value to represent them for which SQL Server does not provide a scalar type. Dimensions in a mechanical drawing, for example, have quantity value and unit value, like “12 in.” SQL Server 2005 allows a Common Language Runtime, CLR, language to be used to add scalar types and aggregates to SQL Server that can be used in the same way that ...