![](https://csdnimg.cn/release/download_crawler_static/12011383/bg13.jpg)
33.7. Using Descriptor Areas ...............................................................................................812
33.7.1. Named SQL Descriptor Areas ........................................................................812
33.7.2. SQLDA Descriptor Areas ...............................................................................814
33.7.2.1. SQLDA Data Structure.......................................................................815
33.7.2.1.1. sqlda_t Structure ....................................................................815
33.7.2.1.2. sqlvar_t Structure...................................................................816
33.7.2.1.3. struct sqlname Structure ........................................................817
33.7.2.2. Retrieving a Result Set Using an SQLDA .........................................817
33.7.2.3. Passing Query Parameters Using an SQLDA.....................................819
33.7.2.4. A Sample Application Using SQLDA ...............................................820
33.8. Error Handling.............................................................................................................826
33.8.1. Setting Callbacks ............................................................................................826
33.8.2. sqlca ................................................................................................................828
33.8.3. SQLSTATE vs. SQLCODE..................................................................................829
33.9. Preprocessor Directives ...............................................................................................833
33.9.1. Including Files ................................................................................................833
33.9.2. The define and undef Directives .....................................................................834
33.9.3. ifdef, ifndef, else, elif, and endif Directives....................................................835
33.10. Processing Embedded SQL Programs.......................................................................835
33.11. Library Functions ......................................................................................................836
33.12. Large Objects.............................................................................................................837
33.13. C++ Applications ......................................................................................................839
33.13.1. Scope for Host Variables...............................................................................839
33.13.2. C++ Application Development with External C Module .............................840
33.14. Embedded SQL Commands ......................................................................................843
ALLOCATE DESCRIPTOR ......................................................................................843
CONNECT..................................................................................................................845
DEALLOCATE DESCRIPTOR .................................................................................848
DECLARE ..................................................................................................................849
DESCRIBE .................................................................................................................851
DISCONNECT ...........................................................................................................853
EXECUTE IMMEDIATE...........................................................................................855
GET DESCRIPTOR ...................................................................................................856
OPEN ..........................................................................................................................859
PREPARE ...................................................................................................................861
SET AUTOCOMMIT .................................................................................................863
SET CONNECTION ..................................................................................................864
SET DESCRIPTOR....................................................................................................865
TYPE...........................................................................................................................867
VAR.............................................................................................................................870
WHENEVER ..............................................................................................................871
33.15. Informix Compatibility Mode ...................................................................................873
33.15.1. Additional Types...........................................................................................873
33.15.2. Additional/Missing Embedded SQL Statements ..........................................873
33.15.3. Informix-compatible SQLDA Descriptor Areas...........................................874
33.15.4. Additional Functions.....................................................................................877
33.15.5. Additional Constants.....................................................................................886
33.16. Internals .....................................................................................................................887
xix