Data and information models focus on the information content of data stored within an organization and those business systems required to manage that information. Tools are available for database design and SQL generation. Most relational database management systems (RDBMS) use Structured Query Language (SQL) to define the database structure. Most RDBMS vendors support a subset of the SQL-99 standard with some vendor specific extensions. The primary models used for information systems include: Data models identify entities, attributes and relationships Process Models show data flow and transformations Structure models show the calling structure of functions Some systems also use state, task or activity models Return to Design Methods