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Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
ESQL/C Guide
The Informix® ESQL/C Programmer's Manual explains how to use Informix ESQL/C, the Informix implementation of Embedded Structured Query Language (SQL) for C (ESQL/C), to create client applications with database-management capabilities.
Dynamic SQL
Determine SQL statements
If you do not know until run time what SQL statement to execute, you can dynamically determine that statement with the DESCRIBE statement and use a dynamic-management structure to hold any values that the statement sends to or receives from the database server.
Determine statement information at run time

Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
- Change Data Capture API Programmer's Guide
  The Informix® Change Data Capture API Programmer's Guide describes how to program applications to process changed data from HCL Informix databases using the Informix Change Data Capture API.
- Embedded SQLJ for HCL Informix®
  The Informix® Embedded SQLJ User's Guide contains information about using Informix Embedded SQLJ.
- ESQL/C Guide
  The Informix® ESQL/C Programmer's Manual explains how to use Informix ESQL/C, the Informix implementation of Embedded Structured Query Language (SQL) for C (ESQL/C), to create client applications with database-management capabilities.
  - What is Informix® ESQL/C?
  - Database server communication
  - Dynamic SQL
    - Using dynamic SQL
    - Determine SQL statements
      If you do not know until run time what SQL statement to execute, you can dynamically determine that statement with the DESCRIBE statement and use a dynamic-management structure to hold any values that the statement sends to or receives from the database server.
      - Dynamic-management structure
        If you do not know the number or data types of values sent to or received from the database server, use a dynamic-management structure. A dynamic-management structure allows you to pass a variable-length list of data to the database server, or receive a variable-length list of data from it.
      - The DESCRIBE statement
        The DESCRIBE statement obtains information about database columns or expressions in a prepared statement.
      - Determine statement information at run time
        Handling an unknown select list
        Handling an unknown column list
        Determine unknown input parameters
        Determine return values dynamically
        Handling statements that contain user-defined data types
      - A fetch array
        A fetch array enables you to increase the number of rows that a single FETCH statement returns from the fetch buffer to an sqlda structure in your program. A fetch array is especially useful when you fetch simple-large-object (TEXT or BYTE) data.
    - A system-descriptor area
      A system-descriptor area is a dynamic-management structure that can hold data that a prepared statement either returns from or sends to the database server. A system-descriptor area conforms to X/Open standards.
    - An sqlda structure
      An sqlda structure is a dynamic-management structure that can hold data that is either returned from or sent to the database server by a prepared statement. It is a C structure defined in the sqlda.h header file.
  - Appendixes
    This section contains additional reference information.
- GLS User's Guide
  The Informix® GLS User's Guide describes the Global Language Support (GLS) feature available in Informix products.
- API
  The Informix® GLS API Programmer's Guide describes the global language support (GLS) application programming interface (API) available in Informix ESQL/C and HCL Informix DataBlade® modules.
- Informix® Object Interface for C++ Guide
  The Informix® Object Interface for C++ Programmer's Guide describes how to develop HCL Informix client applications by using the object-oriented C++ programming language.
- Informix® ODBC Driver Guide
  The Informix® ODBC Driver Programmer's Manual serves as a user guide and reference for Informix ODBC Driver, which is the Informix implementation of the Microsoft™ Open Database Connectivity (ODBC) interface, Version 3.0.
- .NET provider options
  The Data Server Provider for .NET DB2® provider option is the preferred Informix® provider for developing new applications.
- Informix® JDBC Driver Guide
  The Informix® JDBC Driver Programmer's Guide describes how to install, load, and use Informix JDBC Driver to connect to the Informix database from within a Java™ application or applet.
- Informix International Language Supplement (ILS) User Guide
  These topics include information about the translated user interface files for Informix® UNIX™ products, locales, and code set conversion tables
- Informix® OLE DB Provider Guide
  The Informix® OLE DB Provider Programmer's Guide describes the software requirements for using Informix OLE DB Provider, show how to install and configure the provider for your use, and explain how to use Informix OLE DB Provider to enable client applications, such as ActiveX Data Object (ADO) applications and web pages, to access data on the Informix server.

Determine statement information at run time

Consider a dynamic-management structure when you execute an SQL statement under the following conditions:

Something is not known about the structure of an SQL statement:
- The type of statement to execute is unknown.
- The table name is unknown and therefore the columns to be accessed are unknown.
- The WHERE clause is missing.
Something is not known about the number or type of values that passes between the Informix® ESQL/C program and the database server:
- The number and data types of columns in the select list of a SELECT or in a column list of an INSERT
- The number and data types of input parameters in the statement are unknown
- The number and data types of return values of a user-defined function (executed with the EXECUTE FUNCTION statement) are unknown