ROWIDs in SQLJ with the IBM Data Server Driver for JDBC
and SQLJ
DB2 for z/OS and DB2 for i5/OS support the ROWID data type for a column in a
table. A ROWID is a value that uniquely identifies a row in a table.
Although IBM Informix Dynamic Server (IDS) also supports rowids, those rowids
have the INTEGER data type. You can select an IDS rowid column into a variable
with a four-byte integer data type.
If you use columns with the ROWID data type in SQLJ programs, you need to
customize those programs.
JDBC 4.0 includes interface java.sql.RowId that you can use in iterators and in
CALL statement parameters. If you do not have JDBC 4.0, you can use the IBM
Data Server Driver for JDBC and SQLJ-only class com.ibm.db2.jcc.DB2RowID. For
an iterator, you can also use the byte[] object type to retrieve ROWID values.
The following code shows an example of an iterator that is used to select values
from a ROWID column:
The following code shows an example of calling a stored procedure that takes
three ROWID parameters: an IN parameter, an OUT parameter, and an INOUT
parameter.
#sql iterator PosIter(int,String,java.sql.RowId);
// Declare positioned iterator
// for retrieving ITEM_ID (INTEGER),
// ITEM_FORMAT (VARCHAR), and ITEM_ROWID (ROWID)
// values from table ROWIDTAB
{
PosIter positrowid; // Declare object of PosIter class
java.sql.RowId rowid = null;
int id = 0;
String i_fmt = null;
// Declare host expressions
#sql [ctxt] positrowid =
{SELECT ITEM_ID, ITEM_FORMAT, ITEM_ROWID FROM ROWIDTAB
WHERE ITEM_ID=3};
// Assign the result table of the SELECT
// to iterator object positrowid
#sql {FETCH :positrowid INTO :id, :i_fmt, :rowid};
// Retrieve the first row
while (!positrowid.endFetch())
// Check whether the FETCH returned a row
{System.out.println("Item ID"+id+"Item format " +
i_fmt + " Item ROWID ");
printBytes(rowid.getBytes());
// Use the getBytes method to
// convert the value to bytes for printing
#sql {FETCH :positrowid INTO :id, :i_fmt, :rowid};
// Retrieve the next row
}
positrowid.close(); // Close the iterator
}
Figure 48. Example of using an iterator to retrieve ROWID values
Chapter 4. SQLJ application programming 143
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