Summary

There are several data types available with SQL. If you have programmed in other languages, you probably recognize many of the data types mentioned. Data types allow different types of data to be stored in the database, ranging from simple characters to decimal points to date and time. The concept of data types is the same in all languages, whether programming in a third-generation language such as C and passing variables or using a relational database implementation and coding in SQL. Of course, each implementation has its own names for standard data types, but they basically work the same.

Care must be taken in planning for both the near and distant future when deciding on data types, lengths, scales, and precisions in which to store your data. Business rules and how you want the end user to access the data are other factors in deciding on specific data types. You should know the nature of the data itself and how data in the database is related to assign proper data types.