This chapter discussed the concepts that serve as the foundation for learning the Structured Query Language. The differences between row processing applications and set processing applications (such as relational databases) were discussed. The basic structure of the relational model, both in terms of the ANSI standard and typical database implementations, was illustrated. A quick overview of the datatypes provided by the SQL99 standard, as well as those provided by each database vendor, was also provided. The categories of SQL syntax, including identifiers, literals, system delimiters and operators, and keywords were described. Examples of SQL and an explanation of SQL projections, selections, and joins were included.