Question

I am trying to parameterise all our existing sql, but the following code is giving me a problem:

command.CommandText = String.Format("SELECT * FROM({0}) 
       WHERE ROWNUM <= :maxRecords", command.CommandText);
command.Parameters
       .Add("maxRecords", OracleType.Int32).Value = maxRecords;

The error reported is “ORA-01036: illegal variable name/number”.

I assume that this is because OracleType.Int32 is not the correct datatype for ROWNUM. So what is it?

Answer 1

In SQLPlus we can create a view that includes rownum to see exactly what datatype Oracle uses:

TEST>create view v_test as select rownum rn, dummy from dual;

View created.

TEST>desc v_test
 Name     Null?    Type
 -------- -------- -------------
 RN                NUMBER
 DUMMY             VARCHAR2(1)

So to Oracle, this pseudocolumn is a Number. Which based on this link ( http://download.oracle.com/docs/cd/B28359_01/server.111/b28318/datatype.htm#i16209 ) can hold:

The following numbers can be stored in a NUMBER column:

-Positive numbers in the range 1 x 10^-130 to 9.99...9 x 10^125 with up to 38 significant digits
-Negative numbers from -1 x 10^-130 to 9.99...99 x 10^125 with up to 38 significant digits
-Zero
-Positive and negative infinity (generated only by importing from an Oracle Database, Version 5)