Generating SQL statements, C1DataObjects uses this format string to generate parameter names in the SQL statement. For example, for a SQL Server database, the string can be "@{1}", which will generate parameters like this:

SELECT ... FROM ... WHERE ... = @aName

SQL Server accepts named parameters, so we can use the suggested name (parameter name, {1}) in the SQL statement. Suggested name is usually based on a field name, but it is generally at C1DataObjects discretion. Another possible option for SQL Server can be "@Par{0}", which ignores the suggested name and uses the (unique) parameter number to generate parameter names in the SQL statement. For an Oracle database, a correct format string can be ":{1}" or ":Par{0}".

Reference

CustomProviderInfo Class
CustomProviderInfo Members
ParameterNameFormat Property