Access SQL data types
This section provides an overview of the data types that the DataBlade® API supports.
It also describes DataBlade
API support
for the following types of data:
- Text and strings
- Varying-length structures
- Byte data
- Miscellaneous SQL data types: POINTER, BOOLEAN, and simple large objects
- The MI_DATUM structure
- The NULL constant
For references to discussions of different SQL data types in these topics, see Correspondence of SQL data types to DataBlade API data types.
DataBlade
API, C,
and SQL data types lists
the correspondences between SQL and DataBlade
API data
types. To declare a variable for an SQL data type, use the appropriate DataBlade
API predefined
data type or structure for the variable. The mi.h header
file includes the header files for the definitions of all DataBlade
API data
types. Include mi.h in all DataBlade
API modules
that use DataBlade
API data
types.
The DataBlade
API represents
the SQL data type of a column value with the following data type structures:
- A short name, called the type identifier, which identifies only the data type
- A long name, called the type descriptor, which provides the data type and information about this type
Server only: Type descriptors
and type identifiers do not have an associated memory duration. The DataBlade
API allocates
them from a special data type cache.