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SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Guide to SQL: Syntax
The Informix® Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the Informix dialect of the SQL language.
Other syntax segments
These topics describe syntax segments, which are language elements, such as database object names or optimizer directives, that appear as a subdiagram reference in the syntax diagrams of some SQL or SPL statements.
Identifier
An identifier specifies the unqualified name of a database object, such as an access method, aggregate, alias, blobspace, cast, column, constraint, correlation, data type, index, operator class, partition, procedure, table, trigger, sequence, synonym, or view. Use the Identifier segment whenever you see a reference to an identifier in a syntax diagram.
Enabling Delimited Identifiers

SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
- Guide to SQL: Syntax
  The Informix® Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the Informix dialect of the SQL language.
  - Overview of SQL syntax
    These topics provide an overview about how to use the SQL statements, SPL statements, and syntax segments.
  - SQL statements
    This chapter describes the syntax and semantics of SQL statements that are recognized by Informix®.
  - SPL statements
    These topics describe Stored Procedure Language (SPL) statements, which you use to write SPL routines. You can store these routines in the database as user-defined routines (UDRs).
  - Data types and expressions
    These topics describe the data types and expressions that Informix®supports.
  - Other syntax segments
    These topics describe syntax segments, which are language elements, such as database object names or optimizer directives, that appear as a subdiagram reference in the syntax diagrams of some SQL or SPL statements.
    - Arguments
    - Collection-Derived Table
      A collection-derived table is a virtual table in which the values in the rows of the table are equivalent to elements of a collection. Use this segment where you see a reference to Collection-Derived Table in a syntax diagram. This syntax is an extension to the ANSI/ISO standard for SQL.
    - Database Name
    - Database Object Name
    - External Routine Reference
      Include the External Routine Reference clause when you write an external routine. This option is not available for SPL routines.
    - Identifier
      An identifier specifies the unqualified name of a database object, such as an access method, aggregate, alias, blobspace, cast, column, constraint, correlation, data type, index, operator class, partition, procedure, table, trigger, sequence, synonym, or view. Use the Identifier segment whenever you see a reference to an identifier in a syntax diagram.
      - Use of Uppercase Characters
      - Use of Keywords as Identifiers
      - Support for Non-ASCII Characters in Identifiers
      - Delimited Identifiers
      - Enabling Delimited Identifiers
        Examples of Delimited Identifiers
        Using Double Quotation Marks in a Delimited Identifier
      - Potential Ambiguities and Syntax Errors
      - Using the Names of Built-In Functions as Column Names
      - Using Keywords as Column Names
      - Using ALL, DISTINCT, or UNIQUE as a Column Name
      - Using INTERVAL or DATETIME as a Column Name
      - Using rowid as a Column Name
      - Using keywords as table names
        The database server issues an error in contexts where the unqualified identifier of a table object is also a valid keyword of SQL. You can disambiguate the table name by qualifying it with the authorization identifier of the owner of the table.
    - Jar Name
      Use the Jar Name segment to specify the name of a jar ID. Use this segment whenever you see a reference to Jar Name in a syntax diagram.
    - Optimizer Directives
      The Optimizer Directives segment specifies keywords that you can use to partially or fully specify the query plan of the optimizer. Use this segment whenever you see a reference to Optimizer Directives in a syntax diagram.
    - Owner name
      The owner name specifies the owner of a database object. Use this segment whenever you see a reference to Owner Name in a syntax diagram.
    - Purpose Options
    - Return Clause
    - Routine modifier
      A routine modifier specifies characteristics of how a user-defined routine (UDR) behaves.
    - Routine Parameter List
    - Shared-Object Filename
      Use a shared-object filename to specify a pathname to an executable object file when you register or alter an external routine.
    - Specific Name
    - Statement Block
  - Built-In Routines
  - Appendixes
- Guide to SQL: Reference
  The Informix® Guide to SQL: Reference contains the reference information for the system catalog tables, data types, and environment variables of the HCL Informix dialect of the SQL language, as implemented in HCL Informix. These topics also include information about the stores_demo, sales_demo, and superstore_demo databases that are included with HCL Informix.
- Guide to SQL: Tutorial
  The Informix® Guide to SQL: Tutorial shows how to use basic and advanced structured query language (SQL) to access and manipulate the data in your databases. It discusses the data manipulation language (DML) statements as well as triggers and stored procedure language (SPL) routines, which DML statements often use.

Enabling Delimited Identifiers

About this task

To use delimited identifiers, you must set the DELIMIDENT environment variable. While DELIMIDENTis set, strings enclosed in double quotation marks ( " ) are treated as identifiers of database objects, and strings enclosed in single quotation marks ( ' ) are treated as literal strings. If the DELIMIDENT environment variable is not set, however, strings enclosed in double quotation marks are also treated as literal strings.

If DELIMIDENT is set, the SELECT statement in the following example must be in single quotation marks in order to be treated as a quoted string:

PREPARE ... FROM 'SELECT * FROM customer';

If a delimited identifier is used in the SELECT statement that defines a view, then the DELIMIDENT environment variable must be set in order for the view to be accessed, even if the view name itself contains no special characters.

On UNIX™ and Linux™ systems, you can set DELIMIDENT by the procedures for setting environment variables that are described in Informix® Guide to SQL: Reference.

On Windows™ systems, you can set DELIMIDENT in various ways, which generally have the following descending order of precedence:

The setting of DELIMIDENT in the connection string when connecting
The setting of the SQL_INFX_ATTR_DELIMIDENT connection attribute before connecting
The setting of DELIMIDENT in setnet32 with the Use my settings box selected
The setting of DELIMIDENT in setnet32 with the Use my settings box cleared
The setting of DELIMIDENT on the command line before running the application
The setting of DELIMIDENT in Windows™ as a user variable
The setting of DELIMIDENT in Windows™ as a system variable
The default value (of no support for delimited identifiers).

This general order of precedence for Windows™ clients is sensitive, however, to the API through which you connect to the database, which can also affect the meaning of the setting and the default value. Refer to the documentation of your specific API for more information about the DELIMIDENT setting in Windows™.