Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

Inside a relational database management system, the princi­pal persisted data structure is considered a logical relation. Operations performed against that data within the RDBMS result in a logical ...

The beauty and joy of a relational database is the concept of relational closure—everything is a table. Beyond the eponymous table, query results are also “tables.” Any query serves as a table to be ...

When the interface view engine reads data from a CA-OpenIngres table or view, an SQL SELECT statement is issued to place a shared lock on the table. (A shared lock enables more than one user to access ...