Major Description
BACKGROUND:
When connecting to a Derby db with a user id and password, the default schema is USER. For example, if I connect with:
ij> connect 'jdbc:derby:myDB;user=someUser;password=somePwd';
then the default schema is "SOMEUSER".
PROBLEM:
It turns out that if a table t1 exists in a non-default schema and the default schema (in this case, "SOMEUSER") doesn't exist yet (because no objects have been created in that schema), then attempts to create a trigger on t1 using its qualified name will lead to a null pointer exception in the Derby engine.
REPRO:
In ij:
– Create database with default schema "SOMEUSER".
ij> connect 'jdbc:derby:myDB;create=true;user=someUser;password=somePwd';
– Create table t1 in a non-default schema; in this case, call it "ITKO".
ij> create table itko.t1 (i int);
0 rows inserted/updated/deleted
– Now schema ITKO exists, and T1 exists in schema ITKO, but default schema SOMEUSER does NOT exist, because we haven't created any objects in that schema yet.
– So now we try to create a trigger in the ITKO (i.e. the non-default) schema...
ij> create trigger trig1 after update on itko.t1 for each row mode db2sql select * from sys.systables;
ERROR XJ001: Java exception: ': java.lang.NullPointerException'.
A look at the derby.log file shows the stack trace given below. In a word, it looks like the "compilation schema" field of SYS.SYSTRIGGERS isn't getting set, and so it ends up being null. That causes the NPE in subsequent processing...
java.lang.NullPointerException
at org.apache.derby.impl.sql.catalog.SYSSTATEMENTSRowFactory.makeSYSSTATEMENTSrow(SYSSTATEMENTSRowFactory.java:200)
at org.apache.derby.impl.sql.catalog.DataDictionaryImpl.addSPSDescriptor(DataDictionaryImpl.java:2890)
at org.apache.derby.impl.sql.execute.CreateTriggerConstantAction.createSPS(CreateTriggerConstantAction.java:354)
at org.apache.derby.impl.sql.execute.CreateTriggerConstantAction.executeConstantAction(CreateTriggerConstantAction.java:258)
at org.apache.derby.impl.sql.execute.MiscResultSet.open(MiscResultSet.java:56)
at org.apache.derby.impl.sql.GenericPreparedStatement.execute(GenericPreparedStatement.java:366)
at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(EmbedStatement.java:1100)
at org.apache.derby.impl.jdbc.EmbedStatement.execute(EmbedStatement.java:509)
at org.apache.derby.impl.jdbc.EmbedStatement.execute(EmbedStatement.java:467)
at org.apache.derby.impl.tools.ij.ij.executeImmediate(ij.java:299)
at org.apache.derby.impl.tools.ij.utilMain.doCatch(utilMain.java:433)
at org.apache.derby.impl.tools.ij.utilMain.go(utilMain.java:310)
at org.apache.derby.impl.tools.ij.Main.go(Main.java:210)
at org.apache.derby.impl.tools.ij.Main.mainCore(Main.java:176)
at org.apache.derby.impl.tools.ij.Main14.main(Main14.java:56)
at org.apache.derby.tools.ij.main(ij.java:60)