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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.
Database Object Name
Specifying a Database Object in an External Database
Specifying a Database Object in a Cross-Database Query

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
      - Specifying a Database Object in an External Database
        Specifying a Database Object in a Cross-Database Query
        Specifying a Database Object in a Cross-Server Query
        To specify an object in a database of a remote database server, you must use a fully-qualified identifier that specifies the database, the database server instance, and the owner (if the external database is ANSI compliant), in addition to the database object name.
      - Routine Overloading and Routine Signatures
      - Owners of Objects Created by UDRs
    - 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
    - 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.

Specifying a Database Object in a Cross-Database Query

To specify an object in another database of the local database server, you must qualify the identifier of the object with the name of the database (and of the owner, if the external database is ANSI compliant), as in this example:

corp_db:hrdirector.executives

In this example, the name of the external database is corp_db. The name of the owner of the table is hrdirector. The name of the table is executives. Here the colon ( : ) separator is required after the database qualifier.

In Informix®, queries and other data manipulation language (DML) operations on other databases of the local database server can access most of the built-in opaque data types, as listed in Data Types in Cross-Database Transactions. DML operations can also access user-defined data types (UDTs) that can be cast to built-in types, as well as DISTINCT types that are based on built-in types, if each DISTINCT types and UDT is cast explicitly to a built-in type, and if all the DISTINCT types, UDTs, and casts are defined in all of the participating databases. The same data-type restrictions also apply to the arguments and to the returned values of a user-defined routine (UDR) that accesses other databases of the local Informix® instance, if the UDR is defined in all of the participating databases.