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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.
Routine Parameter List

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.
    - 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
      - Subset of SQL Data Types
      - Using the LIKE Clause
      - Using the REFERENCES Clause
      - Using the DEFAULT Clause
      - Specifying OUT Parameters for User-Defined Routines
      - Specifying INOUT Parameters for a User-Defined Routine
        UDRs that are written in the SPL, C, or Java™ languages can also support INOUT parameters. When the UDR is invoked, a value for each INOUT parameter is passed by reference as an argument to the UDR.
    - 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.

Routine Parameter List

Use the appropriate part of the Routine Parameter List segment whenever you see a reference to a Routine Parameter List in a syntax diagram.

Syntax

^{(explicit id ropal002)
ropal002} ^{(explicit id ropal003)
ropal003}

Routine Parameter List

[ { IN | OUT | INOUT } ] <Parameter>

Parameter

{ parameter | ^[] }

{ { <Subset of SQL Data Type> ^[] | LIKE table.column } [ DEFAULTvalue ] | REFERENCES { BYTE | TEXT } [ DEFAULT NULL ] }


Element	Description	Restrictions	Syntax
column	Name of a column whose data type is declared for parameter	Must exist in the specified table	Database Object Name
parameter	Name of a parameter of the UDR	Name is required for SPL routines	Identifier
table	Table that contains column	The table must exist in the database	Identifier
value	Default used if UDR is called with no value for parameter	Must be a literal, of the same data type as parameter. For opaque types, an input function must be defined	Literal Number

Usage

A parameter is a formal argument in the declaration of a UDR. (When you subsequently invoke a UDR that has parameters, you must substitute a specific argument value for the parameter, unless the parameter has a default value.)

The name of the parameter is optional for external routines of HCL Informix®.

When you create a UDR, you declare a name and data type for each parameter. You can specify the data type directly, or use the LIKE or REFERENCES clause to specify the data type. You can optionally specify a default value.

You can define any number of SPL routine parameters, but the total length of all parameters passed to an SPL routine must be less than 2 gigabytes.

No more than nine arguments to a UDR written in the Java™ language can be DECIMAL data types of SQL that the UDR declares as BigDecimal data types of the Java™ language.

Any C language UDR that returns an opaque data type must specify opaque_type in the var binary declaration of the C host variable.

¹ External routines only

² See Subset of SQL Data Types