6.8. NULLs and Host Languages
This book does not discuss using SQL statements embedded in any particular host language. For that information, you will need to pick up a book for your particular language. However, you should know how NULLs are handled when they have to be passed to a host program. No standard host language for which an embedding is defined supports NULLs, which is another good reason to avoid using them in your database schema.
Roughly speaking, the programmer mixes SQL statements bracketed by EXEC SQL and a language-specific terminator (the semicolon in Pascal and C, END-EXEC in COBOL, and so on) into the host program. This mixed-language program is run through an SQL preprocessor that converts the SQL into procedure calls the ...
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