Search found 76 matches

by Chris Walton
Wed May 06, 2015 10:25 pm
Forum: Report a Bug
Topic: Automatic error logging - report 157?
Replies: 8
Views: 5049

Re: Automatic error logging - report 157?

The problem seems to have been that multiple updates of JRE and JDK had left my system variables and paths in a mess, pointing to multiple, incompatible versions of the programs. I have now (more or less) sorted out these configuration problems, and thus removed all the problems with Rel. Thanks for...
by Chris Walton
Tue May 05, 2015 11:40 am
Forum: Report a Bug
Topic: Automatic error logging - report 157?
Replies: 8
Views: 5049

Re: Automatic error logging - report 157?

Clearing down ALL the databases and recreating the relevant ones seems to have done the trick. I have not re-checked the JDK and JRE versions but when I started this thread I had got different versions and had to upgrade JDK.
by Chris Walton
Mon May 04, 2015 4:19 pm
Forum: Report a Bug
Topic: Automatic error logging - report 157?
Replies: 8
Views: 5049

Re: Automatic error logging - report 157?

Yes, the problem directories do have existing databases, in subdirectory Database. Deleting this subdirectory and restarting Rel makes no difference to the error reporting. Again once the error messages have been OKed, a database can be opened (or created) and things carry on as normal.
by Chris Walton
Sun May 03, 2015 8:51 pm
Forum: Report a Bug
Topic: Automatic error logging - report 157?
Replies: 8
Views: 5049

Re: Automatic error logging - report 157?

I think the problems I am having with start up are something to do with the configuration of my machine or JVM. On investigating it, I have incidentally found some odd behaviour on start up. My database is found in a directory with quite a long pathname. I started DBrowser using only part of the pat...
by Chris Walton
Thu Apr 30, 2015 11:41 pm
Forum: Report a Bug
Topic: Automatic error logging - report 157?
Replies: 8
Views: 5049

Automatic error logging - report 157?

Further to the recently automatically submitted error log, I am getting the following message when I start up Rel. Capture.PNG Even though it reports an error the Browser does start - seemingly OK. In addition starting Rel (using DBrowser.bat) starts the monitor but I have to manually start the Brow...
by Chris Walton
Sun Feb 16, 2014 8:27 pm
Forum: Language Issues
Topic: NullOps
Replies: 1
Views: 1723

NullOps

What syntax should be used to say "do nothing". Both the following fragments of code generate errors: OPERATOR TestOps ( T RELATION SAME_HEADING_AS ( red.Tree ) ) RETURNS RELATION SAME_HEADING_AS ( red.Tree ); BEGIN; VAR i INTEGER INIT ( 0 ); FOR UNION { EXTEND T : { parent := i } } ORDER ( ASC pare...
by Chris Walton
Thu Jan 23, 2014 6:31 pm
Forum: Language Issues
Topic: DEE and DUM
Replies: 2
Views: 2057

Re: DEE and DUM

I was not clear enough about what I was trying to do. I was trying to insert, into a relvar which has a RVA, values which contained an empty relation for the RVA. After some experimentation I have found the following works. VAR T1 BASE RELATION { A0 CHAR, R0 RELATION { B1 INT, B2 CHAR } } KEY { A0 }...
by Chris Walton
Fri Jan 10, 2014 1:52 pm
Forum: Language Issues
Topic: SET
Replies: 1
Views: 1410

SET

What is the SET extension intended for, and what is its intended use? It is not mentioned in the list of extensions, and in this instance the grammar statement "set ::= <SET> identifier identifier" is not very helpful.
by Chris Walton
Thu Jan 09, 2014 8:53 pm
Forum: Language Issues
Topic: DEE and DUM
Replies: 2
Views: 2057

DEE and DUM

I have not got the usage of DEE and DUM sorted out. How do I amend the following examples to initialise a relvar to empty? VAR Test BASE RELATION { A0 INT } INIT ( RELATION { TUPLE { A0 999 } } ) KEY { A0 }; Ok. VAR Test1 BASE RELATION { A0 INT } INIT ( DEE ) KEY { A0 }; ERROR: Variable of type RELA...
by Chris Walton
Fri Jan 03, 2014 6:36 pm
Forum: Language Issues
Topic: Variable scoping
Replies: 4
Views: 2390

Re: Variable scoping

Your responses are very helpful, and enable me to continue making progress with what I am trying to do.

Sorry, if in raising this question, I broke your code of omerta in respect of variable scoping. :lol:
by Chris Walton
Thu Jan 02, 2014 5:07 pm
Forum: Language Issues
Topic: Variable scoping
Replies: 4
Views: 2390

Re: Variable scoping

Thanks for the information. Can I just confirm one of my inferences from what you say: Given what you say in your code, operator p() returns integer; begin; var x init(2); begin; var y init(3); end; return x + y; end; end operator; I infer that variables are not usable within recursive calls ie: ope...
by Chris Walton
Wed Jan 01, 2014 4:52 pm
Forum: Language Issues
Topic: Variable scoping
Replies: 4
Views: 2390

Variable scoping

What is the scope of variables used in Rel? I have had a (brief) look at DTARM and the Rel grammar and cannot determine this. I assume that any REAL, VIEW, or PUBLIC variable has a database wide scope - ie effectively such variables are all global variables. What about PRIVATE variables? What about ...
by Chris Walton
Fri Dec 13, 2013 5:59 pm
Forum: Language Issues
Topic: Ungrouping complex relvars
Replies: 1
Views: 1546

Ungrouping complex relvars

While I know there may be issues with relation valued attributes, and their use often does not constitute the best principles of design; it is convenient to make use of this relvar "Entity.structures" at a specific point in my development: // Input and response Entity.structures RELATION {name ID, s...
by Chris Walton
Tue Dec 03, 2013 1:11 am
Forum: Report a Bug
Topic: User defined operators
Replies: 1
Views: 1632

User defined operators

The following sequence works correctly:

Code: Select all

OPERATOR U0 ( a1 CHAR ) RETURNS CHAR;
RETURN "Test";
END OPERATOR;
U0("T2")
whereas:

Code: Select all

OPERATOR U0 ( a1 CHAR );
END OPERATOR;
U0("T2")
gives the following error:

Code: Select all

ERROR: Could not find operator U0(CHARACTER)
by Chris Walton
Fri Nov 29, 2013 12:43 am
Forum: Rel Examples
Topic: Ex11 Clearup database script
Replies: 0
Views: 2336

Ex11 Clearup database script

// Database Cleanup Script WRITELN "/*** Clears the database of all user defined elements. ***/"; WRITELN; BEGIN TRANSACTION; FOR UNION { EXTEND sys.Catalog { Name, Owner, CreationSequence } WHERE Owner <> "Rel" : { Deletion := "DROP VAR " || Name || ";" } { CreationSequence, Deletion }, EXTEND sys...