Search found 121 matches

by HughDarwen
Tue Mar 26, 2013 11:50 am
Forum: Report a Bug
Topic: Defining simple view causes loop
Replies: 3
Views: 4088

Re: Defining simple view causes loop

Yes. I deleted those operator definitions and everything then worked fine.

Hugh
by HughDarwen
Sun Mar 24, 2013 4:27 pm
Forum: Report a Bug
Topic: Defining simple view causes loop
Replies: 3
Views: 4088

Defining simple view causes loop

When I create a new v1.0.10 database from the attached backup, various things I attempt to do bring about a loop, reflected by endless repetitions of mysterious messages in the DBrowser Monitor window, as shown in the attachment, loop.d. The third attachment, DefBaseRelvars.d, is one of the scripts ...
by HughDarwen
Wed Mar 13, 2013 4:30 pm
Forum: Discussion
Topic: Question re JAVA_HOME and JDK_HOME
Replies: 2
Views: 7491

Re: Question re JAVA_HOME and JDK_HOME

Many thanks for the clear advice, which worked fine and OperatorsChar.d was executed in a flash. I installed JDK V7.0.7 in a new directory and noticed that its bin subdirectory contains both java.exe and javac.eex. I placed this bin subdirectory in my PATH variable, replacing the previous entry for ...
by HughDarwen
Thu Mar 07, 2013 12:25 pm
Forum: Discussion
Topic: Question re JAVA_HOME and JDK_HOME
Replies: 2
Views: 7491

Question re JAVA_HOME and JDK_HOME

When I execute OperatorsChar.d, for example, the DBrowser monitor gives me repetitions of this message: NOTE: A 'tools.jar' or internal Java compiler can't be found. Make sure JAVA_HOME or JDK_HOME point to a JDK installation. Trying to find an external javac compiler as an alternative. It's only a ...
by HughDarwen
Sun Feb 17, 2013 4:33 pm
Forum: Report a Bug
Topic: multiple assignment problem
Replies: 4
Views: 4743

multiple assignment problem

Against the database that I'll send a backup of privately (because can't get "upload attachment" to work), the following two multiple assignments are equivalent but only the first one works. In version 2, the first line inserts the empty set even though the given expression evaluates to the same rel...
by HughDarwen
Sat Dec 29, 2012 12:39 pm
Forum: Report a Bug
Topic: Expression in op def gives spurious syntax error
Replies: 3
Views: 4097

Re: Expression in op def gives spurious syntax error

If you are suggesting that our Tutorial D V1 syntax was unsound, then I'm glad we fixed it in V2 by introducing a colon to separate the <attribute assign> s from the WHERE clause. I suppose a name followed by an opening paren can be taken for the start of an operator invocation, which might explain ...
by HughDarwen
Fri Dec 28, 2012 5:28 pm
Forum: Report a Bug
Topic: Expression in op def gives spurious syntax error
Replies: 3
Views: 4097

Expression in op def gives spurious syntax error

A certain UPDATE command works fine in DBrowser. When I parameterise it in an operator definition, such that literals are replaced by parameter names, I get an error message that seems to be spurious. I found that enclosing the WHERE condition in parens fixed the problem. Below is an example, copied...
by HughDarwen
Mon May 14, 2012 2:46 pm
Forum: Report a Bug
Topic: Database unusable after exit from DBrowser
Replies: 2
Views: 3450

Database unusable after exit from DBrowser

I'll send a zip file for this separately. The problem, which has been occurring repeatedly with this particular database, is that when I've had an apparently successful DBrowser session in which I've done a few updates, the next time I try to run DBrowser I get the following message: Unable to estab...
by HughDarwen
Sun Apr 15, 2012 2:25 pm
Forum: Report a Bug
Topic: crash that goes away after backup/restore
Replies: 1
Views: 3327

crash that goes away after backup/restore

I'm having to send my (zipped) database folder by private email because the attachment is too large for here. Anyway, the problem concerns the invocation "Problemist not matching (SolvedBy union ComposedBy)" against this database, which has been subject to invocations of INSERT, UPDATE and DELETE. I...
by HughDarwen
Fri Dec 02, 2011 10:32 am
Forum: Rel Examples
Topic: Is SUBSTRING(CHAR, INT, INT) correctly defined?
Replies: 1
Views: 3725

Is SUBSTRING(CHAR, INT, INT) correctly defined?

I refer to the operator provided in OperatorsChar.d. SUBSTRING('abcde',3,4) returns 'd' when I was expecting 'de'. It seems that the start position is using origin 0 while the end position uses origin 1. Alternatively, the third operand is to be interpreted as "up to but not including"--reminiscent ...
by HughDarwen
Fri Dec 02, 2011 10:15 am
Forum: Report a Bug
Topic: spurious error on selector invocation for a UDT value
Replies: 2
Views: 4310

Re: spurious error on selector invocation for a UDT value

Since I reported this "bug" a few minutes ago I discovered that SUBSTRING(CHAR, INTEGER, INTEGER) takes an end position rather than a length as the third operand. So this is in fact a user error and not a bug. However, can I change this into a suggestion for a more explanatory error message. I can u...
by HughDarwen
Fri Dec 02, 2011 9:41 am
Forum: Report a Bug
Topic: spurious error on selector invocation for a UDT value
Replies: 2
Views: 4310

spurious error on selector invocation for a UDT value

The following type definition was accepted by Rel 1.07 beta: type time possrep { c char constraint LENGTH(c) = 5 AND IS_DIGITS(SUBSTRING(c,0,2)) AND IS_DIGITS(SUBSTRING(c,3,2)) AND SUBSTRING(c,2,1) = ':'}; However, time('17:52') results in ERROR: Failure executing external function: java.lang.reflec...
by HughDarwen
Tue Oct 11, 2011 4:25 pm
Forum: Report a Bug
Topic: MAX and MIN don't work when subtype of INTEGER defined
Replies: 2
Views: 3714

Re: MAX and MIN don't work when subtype of INTEGER defined

I can confirm that the same error doesn't arise on version 1.05 beta.

Hugh Darwen
by HughDarwen
Sat Feb 26, 2011 12:43 pm
Forum: Report a Bug
Topic: Problem with most aggregate operators
Replies: 3
Views: 4360

Re: Problem with most aggregate operators

Many thanks, Dave, and sorry for my mistake. I don't know, now, how I managed to convince myself that SUM supported expressions rather than just attribute names, but I tried exactly the same test today and it failed.

Hugh
by HughDarwen
Fri Feb 25, 2011 5:16 pm
Forum: Report a Bug
Topic: Problem with most aggregate operators
Replies: 3
Views: 4360

Problem with most aggregate operators

In the original version of Tutorial D , the syntax for most aggregate operator invocations was <agg op name> ( <rel exp>, <attribute name> ), but eventually we generalized it to allow any expression (usually an open one) in place of <attribute name>. The expression SUM(r, a + 1), where a is a numeri...