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A new issue has been created in JIRA.
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View the issue:
http://issues.apache.org/jira/browse/DERBY-18
Here is an overview of the issue:
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Key: DERBY-18
Summary: Exposed name matching has bugs when the column name is qualified
with a schema name.
Type: Bug
Status: Unassigned
Priority: Minor
Project: Derby
Components:
SQL
Versions:
10.0.2.0
Assignee:
Reporter: Tulika Agrawal
Created: Wed, 29 Sep 2004 12:04 PM
Updated: Wed, 29 Sep 2004 12:04 PM
Description:
Reporting for Kathey Marsden.
create table t1(c1 int); -- goes into app
select sys.t1.c1 from t1; -- should fail
select sys.b.c1 from t1 b; -- should fail
select * from t1, app.t1; -- fails, should succeed
select t1.c1 from t1, app.t1; -- fails, should succeed
- According to SQL92, the <table
name> in a <table reference> exposes its name when it is not
qualified (See 6.3 <table reference>, Syntax Rule 1). Also,
an unqualified <table name> is equivalent to one qualified
with the current default schema name (See 5.4 Names and
identifiers, Syntax Rule 8). So, in the above queries,
select * from t1, app.t1 -- is the same as select * from
app.t1, app.t1, and this is not SQL92 --- you have duplicate
exposed <table name>s in the same scope (see 6.3 <table
reference>, Syntax Rule 3). Derby can support it, but it's an
extension.
select t1.c1 from t1, app.t1 -- is the same as select app.t1.c1
from app.t1, app.t1, and again supporting this would be an
extension to SQL92.
Note that if you say
select * from t1, t2 t1 -- this is also a duplication, as the
exposed <table name> of the first table is app.t1 and the
exposed <correlation name> of the second table is t1. these
are different names, but 6.3 <table reference> Syntax Rule 4
rules out this case explicitly -- a <correlation name>
cannot be the same as the unqualified part of any exposed
<table name>.
One possibility is to go to a 2 pass method of column resolution:
1st pass looks for an exact match on the qualifier (app.t1
matches app.t1 but not t1, ...)
if no match, then do 2nd pass where it looks for a match on
table id.
(Look at OrderByColumn.bindOrderByColumn()
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