DOCUMENT:Q179298 11-DEC-1999 [foxpro] TITLE :PRB: Null RuleExpression, RuleText, and Default View Properties PRODUCT :Microsoft FoxPro PROD/VER:MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0,5.0a OPER/SYS: KEYWORDS:kbHWMAC kbvfp ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual FoxPro for Macintosh, version 3.0b - Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a ------------------------------------------------------------------------------- SYMPTOMS ======== The following error message is returned when you attempt to use a view: Error reading a property from the database. The property is ignored. CAUSE ===== Setting the RuleExpression, RuleText, and/or the Default property of a view field to an illegal value causes this behavior. Examples of illegal values include the null string ("") or setting a RuleExpression property to a text string, such as "This field cannot be empty." RESOLUTION ========== In order to prevent the error message from appearing it is necessary to re- create the view with valid field properties. The following code re-creates a view from the view definition stored in the database container: PARAMETER viewname thisversion=VERSION() IF LEFT(ALLTRIM(thisversion),6)="Visual" thisversion=VAL(SUBSTR(thisversion,15,2)) ELSE thisversion=0 ENDIF SET EXCLUSIVE ON SET MULTILOCKS ON DECLARE viewprops[1,5] OPEN DATABASE home()+"\SAMPLES\DATA\TESTDATA" EXCL sql_statement=DBGETPROP(viewname,"VIEW","SQL") llsendupdates=DBGETPROP(viewname,'View','SendUpdates') lnupdatetype=DBGETPROP(viewname,'View','UpdateType') lnwheretype=DBGETPROP(viewname,'View','WhereType') lnbatchupdatecount=DBGETPROP(viewname,'View','BatchUpdateCount') lnusememosize=DBGETPROP(viewname,'View','UseMemoSize') lnfetchsize=DBGETPROP(viewname,'View','FetchSize') llfetchmemo=DBGETPROP(viewname,'View','FetchMemo') lnmaxrecords=DBGETPROP(viewname,'View','MaxRecords') lctables=DBGETPROP(viewname,'View','Tables') lccomment=DBGETPROP(viewname,'View','Comment') IF thisversion>=5 llprepared=DBGETPROP(viewname,'View','Prepared') llcomparememo=DBGETPROP(viewname,'View','CompareMemo') llfetchasneeded=DBGETPROP(viewname,'View','FetchAsNeeded') ENDIF USE &viewname =AFIELDS(viewflds,viewname) USE FOR i=1 TO ALEN(viewflds,1) DIMENSION viewprops[i,5] fld_name=viewflds[i,1] viewfield=ALLTRIM(viewname)+"."+ALLTRIM(fld_name) viewprops[i,1]=DBGETPROP(viewfield,'Field','KeyField') viewprops[i,2]=DBGETPROP(viewfield,'Field','Updatable') viewprops[i,3]=DBGETPROP(viewfield,'Field','UpdateName') viewprops[i,4]=DBGETPROP(viewfield,'Field','DataType') viewprops[i,5]=DBGETPROP(viewfield,'Field','Caption') NEXT DELETE VIEW &viewname CREATE SQL VIEW &viewname AS &sql_statement =DBSETPROP(viewname,'View','SendUpdates',llsendupdates) =DBSETPROP(viewname,'View','UpdateType',lnupdatetype) =DBSETPROP(viewname,'View','WhereType',lnwheretype) =DBSETPROP(viewname,'View','BatchUpdateCount',lnbatchupdatecount) =DBSETPROP(viewname,'View','UseMemoSize',lnusememosize) =DBSETPROP(viewname,'View','FetchSize',lnfetchsize) =DBSETPROP(viewname,'View','FetchMemo',llfetchmemo) =DBSETPROP(viewname,'View','MaxRecords',lnmaxrecords) =DBSETPROP(viewname,'View','Tables',lctables) =DBSETPROP(viewname,'View','Comment',lccomment) IF thisversion>=5 =DBSETPROP(viewname,'View','Prepared',llprepared) =DBSETPROP(viewname,'View','CompareMemo',llcomparememo) =DBSETPROP(viewname,'View','FetchAsNeeded',llfetchasneeded) ENDIF FOR i=1 TO ALEN(viewflds,1) fld_name=viewflds[i,1] viewfield=ALLTRIM(viewname)+"."+ALLTRIM(fld_name) =DBSETPROP(viewfield,'Field','KeyField',viewprops[i,1]) =DBSETPROP(viewfield,'Field','Updatable',viewprops[i,2]) =DBSETPROP(viewfield,'Field','UpdateName',viewprops[i,3]) =DBSETPROP(viewfield,'Field','DataType',viewprops[i,4]) =DBSETPROP(viewfield,'Field','Caption',viewprops[i,5]) NEXT RETURN STATUS ====== Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available. MORE INFORMATION ================ When a view is created, the default value for the RuleExpression, RuleText, and Default field properties is a null string. Steps to Reproduce Behavior --------------------------- 1. Create a program called Bogus.prg with the following code: OPEN DATABASE home()+"\SAMPLES\DATA\TESTDATA" CREATE SQL VIEW customerview ; AS SELECT DISTINCT cust_id, company, contact ; FROM testdata!customer ; ORDER BY customer.cust_id =DBSETPROP('CUSTOMERVIEW.Cust_id','Field','RuleExpression', ; 'len(alltrim(cust_id))>0') && Fails with null. =DBSETPROP('CUSTOMERVIEW.Cust_id','Field','RuleText', ; "this field cannot be empty") && Fails either way. =DBSETPROP('CUSTOMERVIEW.Cust_id','Field','Default', ; "alltrim(str(reccount()+1))") && Fails with null. =DBSETPROP('customerview.Company','Field','RuleExpression', ; 'company<>0') && Fails with null. =DBSETPROP('customerview.Company','Field','RuleText', ; "it cannot be empty") =DBSETPROP('customerview.Company','Field','Default', ; 'reccount()+1') && Fails with null. USE CUSTOMERVIEW BROWSE 2. In the FoxPro Command window type "DO Bogus". When the program runs and the view is used, the following error message is displayed twice: Error reading a property from the database. The property is ignored. Additional query words: ====================================================================== Keywords : kbHWMAC kbvfp Technology : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbVFP300bMac kbVFP300 kbVFP300b kbVFP500 kbVFP500a Version : MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0,5.0a Issue type : kbprb ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.