[V4RB] API Equivalent of UPDATE WHERE

[Ruslan Zasukhin]

On 1/3/05 9:53 PM, "Frank Schima" <frank-list3 at mindstarprods.com> wrote:

Hi Frank,
 
> With all this talk about the API way being faster than SQL, I was
> wondering what is the equivalent code for UPDATE... WHERE... with the
> new V4RB API?
> 
> UpdateRecord will update a single record, and UpdateAllRecords will
> update all the records of a table/cursor. So how can I update a subset
> of records without looping through them all and using UpdateRecord?
> 
> Basically I'm looking for an API workaround for that UPDATE SQL
> statement that is crashing for me. Namely:
> 
>     UPDATE MyTable Set MyVarcharField = 'some text' WHERE MyVarcharField
> is Null
> 
> Pseudo-code please? :^)

* But what is bad in looping ?
    if this is local db then no problems in fact,
    RB is fast on this.

* API way will require more coding. This is a RULE.

    so the pure API way can be:

    set = fldVarChar.FindNulls()

    Iter = set.MakeNewIterator
    recid = Iter.first

    do
        tbl.RecID = recid
        fldVarChar.value = "some text"
        tbl.UpdateRecord()
    
    while recid = iter.next


* Also your task CAN be made with UpdateAllRecords() as I see.

    curs = db.SqlSelect(
                "SELECT MyVarcharField WHERE MyVarcharField IS NULL" )

    curs.VarCharField(x).valule = "someText"

    curs.UpdateAllRecords()


* keep in mind that API way cannot do JOINS, GROUP BY and so on.
    this is RELATIONAL Model features, mirrored in the SQL.



-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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