Host variables are C variables that are identified to the SQL preprocessor. Host variables can be used to send values to the database server or receive values from the database server.
Host variables are quite easy to use, but they have some restrictions. Dynamic SQL is a more general way of passing information to and from the database server using a structure known as the SQL Descriptor Area (SQLDA). The SQL preprocessor automatically generates a SQLDA for each statement in which host variables are used.
You cannot use host variables in batches.
For information about dynamic SQL, see Static and dynamic SQL.
Declaring host variables
C host variable types
Host variable usage