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Extending Informix®Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix® includes many built-in extensions that are fully integrated in the database server. Informix® also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix®.
Creating extensionsYou can create user-defined data types, routines, access methods, and other database objects to suit your needs. You can use application programming interfaces to write user-defined routines and applications that access data in Informix® databases.
DataBlade® API Programmer's GuideThe Informix® DataBlade® API Programmer's Guide describes information about the DataBlade® API, the C-language application programming interface (API) provided with HCL Informix®.
Data manipulation
Complex data typesThis section describes the complex data types and the functions that the DataBlade® API supports to process collection and row-type data.
Row typesA row type is a complex data type that is made up of a sequence of one or more elements called fields. Each field has a name and a data type. A row type is similar to a C struct data type. The DataBlade® API provides support for row types in both their text and binary representations.
Create a row typeTo create a row type, you create a row structure (MI_ROW) that holds the row type.
Assign the field values
Column-value arrayThe column-value array, col_values, is the third argument of the mi_row_create() function.

Column-value array

The column-value array, col_values, is the third argument of the mi_row_create() function.

Each element of the column-value array is a pointer to an MI_DATUM structure that holds the value for each column. The format of this value depends on whether the MI_DATUM value is passed by reference or by value:

(Server only) For C UDRs, the data type of the value determines the passing mechanism. If the function passes the value by value, the MI_DATUM structure contains the value. If the function passes value by reference, the MI_DATUM structure contains a pointer to the value.
(Client only) For client LIBMI applications, pass all values (regardless of data type) by reference. The MI_DATUM structure contains a pointer to the value.

Important: The difference in behavior of mi_row_create() between C UDRs and client LIBMI applications means that row-creation code is not completely portable between these two types of DataBlade® API module. When you move your DataBlade API code from one of these uses to another, you must change the row-creation code to use the appropriate passing mechanism for column values that mi_row_create() accepts.

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