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JDBC ResultSetMetaData: Wrong Precision Value Returned for Column of Type Number Added by ALTER TABLE Statement (Doc ID 1266785.1)

Last updated on AUGUST 04, 2018

Applies to:

JDBC - Version: and later   [Release: 11.2 and later ]
Oracle Server - Enterprise Edition - Version: to   [Release: 11.1 to 11.2]
Information in this document applies to any platform.


Using JDBC ResultSetMetaData for finding the precision of a column defined as 'not null' will return a precision of 0.
This occurs when obtaining the metadata from a table that was altered by adding a new column of type NUMBER that has a default value and is not null.
For example, if you have the following database structure where the second column added is not null and has a default value.

create table foobar (a number(1) default 0 not null);
alter table foobar add (b number(1) default 0 not null);

running the code:

import java.sql.*;
import java.util.*;
import oracle.jdbc.*;

public class OracleMetaDataTestcase {
private final static String USER = "scott";
private final static String PASSWORD = "tiger";
private final static String TABLENAME = "foobar";

private final static String URL =

public static void main(String[] args) throws SQLException {
Properties properties = new Properties();
properties.setProperty("user", USER);
properties.setProperty("password", PASSWORD);

Driver driver = new OracleDriver();
Connection conn = driver.connect(URL, properties);
try {
Statement statement = conn.createStatement();
try {

// Lastly drop the table so it can be reran
statement.execute("drop table " + TABLENAME);
} finally {
} finally {

private static void createDDL(Statement statement) throws SQLException {
// Create the table here, note that the B column has a default of 0 and is not null
statement.execute("create table " + TABLENAME + " (a number(1) default 0 not null)");
statement.execute("alter table " + TABLENAME + " add (b number(1) default 0 not null)");

private static void checkPrecision(Statement statement) throws SQLException {
// We just do a simple select * from the table.
// This will return no rows and the metadata. This case is only about metadata
ResultSet res = statement.executeQuery("select * from " + TABLENAME);
try {
ResultSetMetaData meta = res.getMetaData();

int columnCount = meta.getColumnCount();
System.out.println("There are " + columnCount + " number of columns - expect 2");

for (int i = 0; i < columnCount; ++i) {
// This fails on the B column. Note it only happens on alter
// of the database table when adding a new column with a default
// and not null. If only one of each is done it works fine.
System.out.println("Column " + (i + 1) + " or " + meta.getColumnName(i + 1) +
" has precision of " + meta.getPrecision(i + 1) + " - expect 1");
} finally {

will output the following:

There are 2 number of columns - expect 2
Column 1 or A has precision of 1 - expect 1
Column 2 or B has precision of 0 - expect 1

where Column B should return a precision of 1.

The problem does not occur if not using default value or null value.
This issue occurs using database version and (regardless of the JDBC driver version used).


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