Statements¶

There are two types of statements in VQL:

1. DDL (Data Definition Language) statements. They allow creating new data sources, wrappers, views, etc. The DDL commands are:

   • CREATE: Creates or replaces new base views, views, stored procedures, wrappers, data sources, published web services, users, etc.

   • DROP: Removes elements such as base views, views, stored procedures, wrappers, data sources, published web services, users, etc.

   • ALTER: Modifies specific properties of views such as its internationalization configuration, cache, swapping configuration, etc. It also allows modifying database and user permissions.

   • DESC: Shows the description of data types, views, stored procedures, maps, operators, wrappers, data sources, etc.

   • LIST: Enumerates the different elements of the catalog (data sources, views, etc.)

   • GRANT and REVOKE: Allow to establish or revoke user permissions over databases, stored procedures and/or views.

2. DML (Data Manipulation Language) statements. They allow querying and updating data. Virtual DataPort provides the following DML statements:

   • SELECT, used to execute queries to the server and define new views. Its syntax is described in the section Queries: SELECT Statement.

   • INSERT, UPDATE and DELETE for inserting, updating and deleting, respectively. See section Materialized Tables for more details about this. These statements can only be executed on views created over JDBC, ODBC or Custom data sources. Furthermore, sometimes it is possible to update views according to the definition of standard SQL-92.

   • BEGIN, COMMIT, ROLLBACK for beginning, committing and rolling back a transaction, respectively.

   • CALL to execute Virtual DataPort stored procedures.