Variable declaration

In a C UDR, you declare variables to hold information just as you would in a C function. The DataBlade API provides many data types for variable declaration.

The DataBlade API adds special prefixes to the names of its data types, as the following table shows.

DataBlade API data type	Data type prefix	More information
Data types to hold SQL data types	mi_	Table 1
Data type structures that hold information for DataBlade API functions	MI_	Table 1

Table 2 lists where in this publication each of the SQL data types is discussed in detail.

Use the DataBlade API data types for variable declaration in your C UDR even if there is a C-language equivalent. The DataBlade API data types are more portable if your C UDR moves to different computer architectures. For more information, see DataBlade API data types.