While working with TpFIBDataSet and TpFIBQuery it is also possible to use in the query macros of the following types:
@ - a sign of the beginning of the macro
% - an optional beginning of the default value of the macro
# - an optional sign that it it necessary to write the value of the macro in inverted commas.
Using macros you can dynamically change names of tables and fields in a query, conditions, etc.
To get access to values of macros use ParamByName. ParamNameCount helps to get the total number of macros in a query.
The example of using of macros:
select * from @TT%TABLE1 where @F%FIELD1=@VAL%#John
The default form of the query before sending off to the server is
select * from TABLE1 where FIELD1="John"