This chapter gives an overview of the most important SQL terms used in the SESAM/SQL manuals. These terms refer to SQL objects created and addressed using the SQL statements or are additional important terms used in the context of SQL. It is assumed that the reader has a general knowledge of relational database systems and of SQL.
The SQL functions are only described in as much detail as is required to understand the remaining chapters of this manual. The SQL statements and language elements are not described in detail. Please refer to the manuals “ SQL Reference Manual Part 1: SQL Statements” and “ SQL Reference Manual Part 2: Utilities” for a complete and systematic description of the SQL statements in SESAM/SQL.
In section “SQL objects of a SESAM/SQL database”, you will find a description of the SQL objects which can be addressed using SQL statements as well as a number of other important SQL concepts. For each of the concepts, a brief description is provided of those SQL statements which are of importance in that context.
In section “SQL statements”, you will find overviews of the individual classes of SQL statements.
In section “Fundamental SQL language resources” you will find descriptions of the language constructs SESAM/SQL uses in SQL statements. These are illustrated briefly, primarily on the basis of examples. This section deals with
the names of SQL objects
the data types recognized by SESAM/SQL
how values, expressions and functions are specified in SQL
how to select rows from a table using a search condition
how to select rows and columns from tables using a query expression
the select expression as an elementary query expression
the join expression, which allows you to link tables together.
the statements SQL provides for manipulating data.
In section “SQL transaction” you will find a description of the SQL statements and concepts which are important in the context of transactions.
In section “Embedding of SQL in programs” you will find a description of how SESAM/SQL users can
access a SESAM/SQL database from a COBOL program
access the rows in a table efficiently using a cursor
implement flexible applications using dynamic SQL statements (i.e. statements which are only interpreted at runtime.
Important concepts regarding access protection in SQL are dealt with in section “Access protection based on privileges in SQL”.