The data provider supports named parameters. A named parameter marker is constructed by an initial character of question mark (?), at-sign (@), or colon (:) followed by a name. The name is an alphanumeric identifier or an integer. Databases vary in the use of the initial character for a named parameter. While the Ingres recommended initial parameter marker character is the question mark, the .NET Data Provider supports all three characters.

If one parameter is named then all of the parameters must be named. If one parameter is unnamed (positional) then all of the parameters must be unnamed. For the sake of code readability, a mix of named parameters and unnamed parameters is not permitted.

For the sake of code readability, a mix of named parameters, each with a different initial parameter marker character in a single SQL statement is also not permitted.

Multiple occurrences of the same named parameter marker in the SQL statement is permitted.

Excess named parameters that are not referenced in the SQL statement are permitted in the IngresParameterCollection and are ignored.

The name comparison between the named parameter marker in the SQL statement and the named parameter in the IngresParameterCollection is not case sensitive.