get last record of group
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From: Paul D B on 19 Nov 2009 03:06 Stephen Quinn wrote: > Paul > >> You'll need to have a descending or custom index to achieve that. > I should qualify that by adding 'as long as your using a relation' > > If you don't use a relationship and set the index scope > programmatically, you could use the Seek() method on DBServer. > > CYA > Steve Hi Steve, I don't think I can do this with an descending index. Say the master file are the Customers. The relation with the detail file is on the field #CustNr. The detail file are the invoices per customer. Each invoice record has a date field. I've got an index order on this detail file with key Str(InvCustNr,6)+DTos(Invdate). The order is Descending so the most recent invoice shows first. So far so good but I wouldn't know how to set a relation that works. AFAIK in a relation you can only specify a field, not an expression. -- Paul
From: Jean-Pierre Maertens on 19 Nov 2009 03:18 from the helpfile : <cbRelationBlock> The relation code block for the server. imo you can specify an expression like : self:odbCustomers:setrelation(self:odbInvoices,{||str(_field->custnr,6)},"str(_field->custnr,6)") > > Hi Steve, > > I don't think I can do this with an descending index. > > Say the master file are the Customers. > The relation with the detail file is on the field #CustNr. > The detail file are the invoices per customer. Each invoice record has a date > field. > I've got an index order on this detail file with key > Str(InvCustNr,6)+DTos(Invdate). The order is Descending so the most recent > invoice shows first. > > So far so good but I wouldn't know how to set a relation that works. AFAIK in > a relation you can only specify a field, not an expression. -- Jean-Pierre Maertens
From: Paul D B on 19 Nov 2009 04:06 Jean-Pierre Maertens wrote: > from the helpfile : > > <cbRelationBlock> The relation code block for the server. > > imo you can specify an expression like : > > self:odbCustomers:setrelation(self:odbInvoices,{||str(_field->custnr,6)},"str(_field->custnr,6)") > > >> >> Hi Steve, >> >> I don't think I can do this with an descending index. >> >> Say the master file are the Customers. >> The relation with the detail file is on the field #CustNr. >> The detail file are the invoices per customer. Each invoice record >> has a date field. >> I've got an index order on this detail file with key >> Str(InvCustNr,6)+DTos(Invdate). The order is Descending so the most >> recent invoice shows first. >> >> So far so good but I wouldn't know how to set a relation that works. >> AFAIK in a relation you can only specify a field, not an expression. Hi JP, long time no hear! Well that works! But I tried something similar earlier but then I only passed in the codeblock. self:odbCustomers:setrelation(self:odbInvoices,{||str(_field->custnr,6)}) and then it does NOT work. I thought the codeblock was enough and that the string parameter was optional. The Help says: cRelationBlock> When the relation is specified as a code block, a string version of the code block *can* be provided as well; it is returned by the Relation() method. Apparantly is is not optional but obligatory. Anyway, many thanks again -- Paul
From: Stephen Quinn on 19 Nov 2009 04:45 Paul A relation is set on a common field in both DBFs The field doesn't have to be in the index expression (of the chld) The child HAS to have an index - in your situ a descending index. > Apparantly is is not optional but obligatory. Providing the string version (as well as/ or instead of the cb only) is always 'safer/better' I've found (VO2.5) CYA Steve
From: Paul D B on 19 Nov 2009 04:55
Stephen Quinn wrote: > Paul > > A relation is set on a common field in both DBFs > The field doesn't have to be in the index expression (of the chld) of the master, you mean... ? -- Paul |