Chapter 34. ECPG — Embedded SQL in C

   Table of Contents

   34.1. The Concept
   34.2. Managing Database Connections

        34.2.1. Connecting to the Database Server
        34.2.2. Choosing a Connection
        34.2.3. Closing a Connection

   34.3. Running SQL Commands

        34.3.1. Executing SQL Statements
        34.3.2. Using Cursors
        34.3.3. Managing Transactions
        34.3.4. Prepared Statements

   34.4. Using Host Variables

        34.4.1. Overview
        34.4.2. Declare Sections
        34.4.3. Retrieving Query Results
        34.4.4. Type Mapping
        34.4.5. Handling Nonprimitive SQL Data Types
        34.4.6. Indicators

   34.5. Dynamic SQL

        34.5.1. Executing Statements without a Result Set
        34.5.2. Executing a Statement with Input Parameters
        34.5.3. Executing a Statement with a Result Set

   34.6. pgtypes Library

        34.6.1. Character Strings
        34.6.2. The numeric Type
        34.6.3. The date Type
        34.6.4. The timestamp Type
        34.6.5. The interval Type
        34.6.6. The decimal Type
        34.6.7. errno Values of pgtypeslib
        34.6.8. Special Constants of pgtypeslib

   34.7. Using Descriptor Areas

        34.7.1. Named SQL Descriptor Areas
        34.7.2. SQLDA Descriptor Areas

   34.8. Error Handling

        34.8.1. Setting Callbacks
        34.8.2. sqlca
        34.8.3. SQLSTATE vs. SQLCODE

   34.9. Preprocessor Directives

        34.9.1. Including Files
        34.9.2. The define and undef Directives
        34.9.3. ifdef, ifndef, elif, else, and endif Directives

   34.10. Processing Embedded SQL Programs
   34.11. Library Functions
   34.12. Large Objects
   34.13. C++ Applications

        34.13.1. Scope for Host Variables
        34.13.2. C++ Application Development with External C Module

   34.14. Embedded SQL Commands

        ALLOCATE DESCRIPTOR — allocate an SQL descriptor area
        CONNECT — establish a database connection
        DEALLOCATE DESCRIPTOR — deallocate an SQL descriptor area
        DECLARE — define a cursor
        DECLARE STATEMENT — declare SQL statement identifier
        DESCRIBE — obtain information about a prepared statement or result
                set

        DISCONNECT — terminate a database connection
        EXECUTE IMMEDIATE — dynamically prepare and execute a statement
        GET DESCRIPTOR — get information from an SQL descriptor area
        OPEN — open a dynamic cursor
        PREPARE — prepare a statement for execution
        SET AUTOCOMMIT — set the autocommit behavior of the current
                session

        SET CONNECTION — select a database connection
        SET DESCRIPTOR — set information in an SQL descriptor area
        TYPE — define a new data type
        VAR — define a variable
        WHENEVER — specify the action to be taken when an SQL statement
                causes a specific class condition to be raised

   34.15. Informix Compatibility Mode

        34.15.1. Additional Types
        34.15.2. Additional/Missing Embedded SQL Statements
        34.15.3. Informix-compatible SQLDA Descriptor Areas
        34.15.4. Additional Functions
        34.15.5. Additional Constants

   34.16. Oracle Compatibility Mode
   34.17. Internals

   This chapter describes the embedded SQL package for PostgreSQL. It was
   written by Linus Tolke (<linus@epact.se>) and Michael Meskes
   (<meskes@postgresql.org>). Originally it was written to work with C. It
   also works with C++, but it does not recognize all C++ constructs yet.

   This documentation is quite incomplete. But since this interface is
   standardized, additional information can be found in many resources
   about SQL.