Usage of Oracle binding variables with LIKE in C#

Question

As part of an effort to stop using dynamic SQL generation and encourage use of bind variables, I am running into some problems.

I am querying an Oracle 9i database from an ASP.NET page using Oracle Data Providers for .NET

The query is

sql = "SELECT somedata FROM sometable WHERE machine = :machineName ";

I define the Oracle Parameter as follows

OracleParameter parameter = new OracleParameter();
parameter.ParameterName = "machineName";
parameter.OracleDbType = OracleDbType.Varchar2;
parameter.Value = machine; //machine is a variable of type string
parameterList.Add(parameter);

This works fine for "=" operator. But I just can't seem to get it to work with "LIKE". I don't know how to format the query so that it accepts usage of the "%" wildcard.

I have tried:

sql = "SELECT somedata FROM sometable WHERE machine LIKE :machineName% ";
sql = "SELECT somedata FROM sometable WHERE machine LIKE ':machineName%' ";
sql = "SELECT somedata FROM sometable WHERE machine LIKE :machineName||% ";

and also:

parameter.Value = machine+'%';

but all I get are ORA-00911 (illegal character) and ORA-01036 (illegal name/value) exceptions.

What am I doing wrong?

Duplicate of this question: http://stackoverflow.com/questions/1412023/constructing-a-good-search-query-using-system-data-oracleclient — CodingGorilla, Sep 24 '10 at 19:48

score 34 · Accepted Answer · answered Sep 24 '10 at 19:48

34

Try:

sql = "SELECT somedata FROM sometable WHERE machine LIKE :machineName || '%' ";

Because of the BIND variable, there wouldn't need to be single quotes around it. But the % is not, so I would expect it needing to be encapsulated.

answered Sep 24 '10 at 19:48

OMG Ponies

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You, sir, are correct. That was indeed the last option, the one I missed. Thank you! – PJ. Sep 24 '10 at 20:00
Thank you so much for this answer! I'm working on a node project with an oracle database driver and was experiencing the same issue. Just out of curiosity, how come I need the two pipes (||) before the wildcard operator (%)? – Dave Cooper Jul 23 '15 at 03:46
2

@DaveCooper the || concatenates the '%', it is a command for concatenation. – Edgar Jul 26 '15 at 00:43
@EdgarRochaCarvalho thank you! Didn't know this - it also explains why it was failing all the times I tried using the + operator! – Dave Cooper Jul 26 '15 at 23:44
This helped me get around the identical issue in our project. Thx! – Dan Mar 03 '20 at 12:12

score 1 · Answer 2 · answered Apr 23 '21 at 16:37

Here is a full query example:

string commandText = "SELECT LastName, FirstName FROM PEOPLE WHERE UPPER(LastName) LIKE '%' || :lastName || '%' AND UPPER(FirstName) LIKE '%' || :firstName || '%'";

string oradb = "yourDatabaseConnectionStringHere"; // Might want to add Using statement for this code and try catch

OracleConnection conn = new OracleConnection(oradb); // C#
conn.Open();
OracleCommand cmd = new OracleCommand
{
     Connection = conn,
     CommandText = commandText,
     CommandType = CommandType.Text
};

/*IMPORTANT: adding parameters must be in order how they are in order in the SQL statement*/
cmd.Parameters.Add(new OracleParameter("lastName", model.LastName.Trim().ToUpper()));
cmd.Parameters.Add(new OracleParameter("firstName", model.FirstName.Trim().ToUpper()));

OracleDataReader dr = cmd.ExecuteReader();

Usage of Oracle binding variables with LIKE in C#

2 Answers2

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