You are a DBA and you want your users to use an isolation level of UR who are doing adhoc queries or typing SQLs using DB2 CLP or some form of the applications.
By using DB2 CLP
Use SET CURRENT ISOLATION LEVEL command
db2 connect to sample db2 set current isolation level UR
In C/C++ programs using DB2 CLI
Set SQLSetConnectAttr function with the SQL_ATTR_TXN_ISOLATION attribute to set the transaction isolation level for the current connection referenced by the ConnectionHandle.
For ODBC, embedded SQL, SQLJ, embedded Cobol
Set value of TXNISOLATION keyword in the db2cli.ini file.
For JDBC JCC Type-IV driver
You can set setTransactionIsolation method in the java.sql interface connection.