Got a c#.net app which I need to modify. The query at the moment effectively does this:
select * from contract where contractnum = :ContractNum
Have yet to find a db that supports evaluating a single string variable containing commas to separate as the sole IN
clause.
Your options are to substring the variable so the comma delimited variable contents are turned into rows, so you can then join onto this. Or to use dynamic SQL, which is a SQL statement constructed as a string in a sproc before the statement is executed.
You can use an Oracle collection of numbers as a parameter (bind variable) when you use ODP.NET as dataprovider. This works with Oracle server 9, 10 or 11 and ODP.net release >= 11.1.0.6.20 .
A similar solution is possible when you use Devart's .NET dataprovider for Oracle.
Let's select the contracts with contractnum's 3 and 4.
We have to use an Oracle type to transfer an array of contract numbers to our query.
MDSYS.SDO_ELEM_INFO_ARRAY
is used because if we use this already predefined Oracle type we don't have to define our own Oracle type. You can fill MDSYS.SDO_ELEM_INFO_ARRAY
with max 1048576 numbers.
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
[OracleCustomTypeMappingAttribute("MDSYS.SDO_ELEM_INFO_ARRAY")]
public class NumberArrayFactory : IOracleArrayTypeFactory
{
public Array CreateArray(int numElems)
{
return new Decimal[numElems];
}
public Array CreateStatusArray(int numElems)
{
return null;
}
}
private void Test()
{
OracleConnectionStringBuilder b = new OracleConnectionStringBuilder();
b.UserID = "sna";
b.Password = "sna";
b.DataSource = "ora11";
using (OracleConnection conn = new OracleConnection(b.ToString()))
{
conn.Open();
using (OracleCommand comm = conn.CreateCommand())
{
comm.CommandText =
@" select /*+ cardinality(tab 10) */ c.* " +
@" from contract c, table(:1) tab " +
@" where c.contractnum = tab.column_value";
OracleParameter p = new OracleParameter();
p.OracleDbType = OracleDbType.Array;
p.Direction = ParameterDirection.Input;
p.UdtTypeName = "MDSYS.SDO_ELEM_INFO_ARRAY";
//select contract 3 and 4
p.Value = new Decimal[] { 3, 4 };
comm.Parameters.Add(p);
int numContracts = 0;
using (OracleDataReader reader = comm.ExecuteReader())
{
while (reader.Read())
{
numContracts++;
}
}
conn.Close();
}
}
}
The index on contract.contractnum isn't used when one omits hint /*+ cardinality(tab 10) */. I assumed contractnum is the primary key so this column will be indexed.
See also here: http://forums.oracle.com/forums/thread.jspa?messageID=3869879#3869879
I know this is an old question but it is one of several in which the selected answer did not solve my problem and I don't want to start yet another thread on this topic so I'll just put down what I found in my travels in the hope that it might help someone.
I don't work with Oracle much but, like in SQL Server, it seems that to pass a table-valued parameter you need to have a corresponding UDT (user defined table) to which you have EXECUTE permissions (I could be wrong). This means that other answers suggesting the use of a built-in SYS UDT come with some freight and I couldn't figure out whether it really is possible to pass a table to something that is not a PL/SQL stored procedure in the current version of ODP.net.
Second, the string-parse solution is a kludge for all the obvious reasons (can't cache the execution plan or whatever Oracle calls it, doesn't scale well, etc).
So I spent rather a lot of time trying do the IN-clause using a table-valued parameter on a datamart to which I have only READ permission before I was hit by a blinding flash of the obvious (At an ASP.net forum no less). Turns out Oracle supports Xml queries 'natively' so instead of passing an array of values you can pass an xml list (if that is all you need). Again, I may be wrong, but it gets handled as a legitimate bind parameter and this is an example of how simple it is to use (vb.net, ADO.net, ODP.net using NuGet package):
Dim xe As New XElement("l", New XElement("i", "ITEM-A"), New XElement("i", "ITEM-B"))
Using conn As New OracleConnection(myConnectionString)
conn.Open()
Using cmd As OracleCommand = conn.CreateCommand()
cmd.CommandType = CommandType.Text
Dim query As String
query = " SELECT s.FOO, q.BAR " & vbCrLf
query &= " FROM TABLE1 s LEFT OUTER JOIN " & vbCrLf
query &= " TABLE2 q ON q.ID = s.ID " & vbCrLf
query &= " WHERE (COALESCE(q.ID, 'NULL') NOT LIKE '%OPTIONAL%') AND "
query &= " (s.ID IN ("
query &= " SELECT stid "
query &= " FROM XMLTable('/l/i' PASSING XMLTYPE(:stid) COLUMNS stid VARCHAR(32) PATH '.')"
query &= " )"
query &= " )"
cmd.CommandText = query
Dim parameter As OracleParameter = cmd.Parameters.Add("stid", OracleDbType.NVarchar2, 4000)
parameter.Value = xe.ToString
Using r As OracleDataReader = cmd.ExecuteReader
While r.Read()
//Do something
End While
End Using
End Using
conn.Close()
This is more of an observation than a carefully researched solution so please comment if there is anything inappropriate about doing it this way.
There is apparently a 4000 character limit using this method (2000 if NVARCHAR) so I had to watch my paging. The informative error message you get if you go over is
ORA-01460: unimplemented or unreasonable conversion requested
you could use a pipelined function to transform a string into a table which could be used with the IN
operator. For example (tested with 10gR2):
SQL> select * from table(demo_pkg.string_to_tab('i,j,k'));
COLUMN_VALUE
-----------------
i
j
k
with the following package:
SQL> CREATE OR REPLACE PACKAGE demo_pkg IS
2 TYPE varchar_tab IS TABLE OF VARCHAR2(4000);
3 FUNCTION string_to_tab(p_string VARCHAR2,
4 p_delimiter VARCHAR2 DEFAULT ',')
5 RETURN varchar_tab PIPELINED;
6 END demo_pkg;
7 /
Package created
SQL> CREATE OR REPLACE PACKAGE BODY demo_pkg IS
2 FUNCTION string_to_tab(p_string VARCHAR2,
3 p_delimiter VARCHAR2 DEFAULT ',')
4 RETURN varchar_tab PIPELINED IS
5 l_string VARCHAR2(4000) := p_string;
6 l_first_delimiter NUMBER := instr(p_string, p_delimiter);
7 BEGIN
8 LOOP
9 IF nvl(l_first_delimiter,0) = 0 THEN
10 PIPE ROW(l_string);
11 RETURN;
12 END IF;
13 PIPE ROW(substr(l_string, 1, l_first_delimiter - 1));
14 l_string := substr(l_string, l_first_delimiter + 1);
15 l_first_delimiter := instr(l_string, p_delimiter);
16 END LOOP;
17 END;
18 END demo_pkg;
19 /
Package body created
Your query would look like this:
select *
from contract
where contractnum in (select column_value
from table(demo_pkg.string_to_tab(:ContractNum)))
For using parameter with IN statement you can use this construction:
select * from contract where contractnum
in (select column_value from table (:ContractNum))
where ContractNum is the custom array type.