SQL statements can use C variables for sending input values to, and receiving output values from, the database. Variables used in this manner are called host variables. Host variables allow an application to use the same statement in an iterative fashion, obtaining results based on the value of the variable when the statement is executed.
PP2 supports structured host variables to a depth of two, following the same rules as SQL/DS and DB2.
Host variables are documented in “Embedded SQL” in Teradata Vantage™ - SQL Stored Procedures and Embedded SQL, B035-1148.