[DERBY-3181] isNullable on ResultSetMetaData from DatabaseMetaData.getBestRowIdentifier values are opposite when there is no rows in ResultSet vs. when there is a row.

• Type: Bug
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 10.4.1.3
• Fix Version/s: 10.13.1.0
• Component/s: JDBC
• Labels: derby_triage10_5_2
• Urgency: Normal
• Issue & fix info: Newcomer, Repro attached
• Assignee: Danoja Dias
• Reporter: Myrna van Lunteren
• Created: 06/Nov/07 23:23
• Updated: 01/Aug/16 06:23
• Resolved: 01/Jun/16 17:07

Description

With code like the following:

DatabaseMetaData dmd = conn.getMetaData();
ResultSet rs = dmd.getBestRowIdentifier(null,"APP","a",3,true);
ResultSetMetaData rsmd = rs.getMetaData();
int actualCols = rsmd.getColumnCount();
for (int i = 0; i < actualCols; i++)

{ System.out.print("getColumnName: " + rsmd.getColumnName(i+1) + ", isNullable: "); System.out.println(rsmd.isNullable(i+1)); }

The printed values for isNullable returned are opposite of what they are when the getBestRowIdentifier call looks like this:
ResultSet rs = dmd.getBestRowIdentifier(null,"APP","a",1,true);

In the latter case, the values are:
getColumnName: SCOPE, isNullable: 0
getColumnName: COLUMN_NAME, isNullable: 1
getColumnName: DATA_TYPE, isNullable: 0
getColumnName: TYPE_NAME, isNullable: 1
getColumnName: COLUMN_SIZE, isNullable: 0
getColumnName: BUFFER_LENGTH, isNullable: 0
getColumnName: DECIMAL_DIGITS, isNullable: 0
getColumnName: PSEUDO_COLUMN, isNullable: 0

In the first case, the values are:
getColumnName: SCOPE, isNullable: 1
getColumnName: COLUMN_NAME, isNullable: 0
getColumnName: DATA_TYPE, isNullable: 1
getColumnName: TYPE_NAME, isNullable: 1
getColumnName: COLUMN_SIZE, isNullable: 1
getColumnName: BUFFER_LENGTH, isNullable: 1
getColumnName: DECIMAL_DIGITS, isNullable: 1
getColumnName: PSEUDO_COLUMN, isNullable: 1

The isNullable value should be stable.
It's probably worthwhile verifying what the value should be in the first place.

Issue Links

• is depended upon by: DERBY-6870 Google Summer of Code 2016: Derby bug fixing