RE: MI Updating columns in Mapbasic

[pel]

Hi Jim

just write this

Select * from MyTab Where _Col2 < 15 into MySelection NoSelect
Set table MyTable Fastedit on

Update MySelection set _col2 = _col3  * _col1      '   this line do the
update

Commit table MyTab
Close table MySelection
Set table MyTAble fastedit off

The Set table mytabel  Fastedit on speed up the proces with a factor 5 or
more, but remember you can not roolback the table again


Med venlig hilsen
Peter Laulund

*************************************************************
Kort & Matrikelstyrelsen  ·  www.kms.dk
National Survey and Cadastre - Denmark
Rentemestervej 8  ·  DK 2400 København NV
E-mail:  [EMAIL PROTECTED]  ·  Home: [EMAIL PROTECTED]
Phone: +45 3587 5050  ·  Direct: +45 3587 5173

*************************************************************




"Jim Wilson" <[EMAIL PROTECTED]> - 2000 09 07 21:18:31

Til:    [EMAIL PROTECTED]
cc:      (bcc: Peter Laulund/MI/KMS)
Vedrørende:    MI Updating columns in Mapbasic




Hi all,

I'm (slowly) learning mapbasic and I'm trying to update the value of  _col2
based on the number in _col3 * _col1. To this end I have tried 2 different
ways of achieving this.
1. Select all the records in Tablename that fall within certain parameters
and then update Tablename from that selection. (the batch approach)
i.e.

Select * From Tablename Where _col1< 15
Fetch First From Selection
Do While Not EOT(Selection)
Update Selection Set _col1 = _col2
Loop

This doesn't work

2. so I tried to loop through all the records in the table updating _col2
based on the value in Tablename._col1
ie

Fetch First from Tablename
 Do While Not EOT(Tablename)
     If (Tablename._col1<=15) Then
         Update Tablename Set _col2=_col3
         ElseIf Tablename._col1>15 and Tablename._col1<=16 Then
         Update Tablename Set _col2=(_col3-((_col3/100)*1.2))
         ElseIf Tablename._col1>16 Then
         Update Tablename Set _col2=(_col3-((_col3_col2/100)*17))
         End If
    Fetch Next From Tablename
Loop

This doesn't work either!
I know this must be a very simple thing to try and do - so could anyone
please point me in the right direction?

                                Thanks,

                                                Jim Wilson

Hi all,

I'm (slowly) learning mapbasic and I'm trying to update the value of  _col2 based on the number in _col3 * _col1. To this end I have tried 2 different ways of achieving this.

1. Select all the records in Tablename that fall within certain parameters and then update Tablename from that selection. (the batch approach)

i.e.

 

Select * From Tablename Where _col1< 15

Fetch First From Selection

Do While Not EOT(Selection)

Update Selection Set _col1 = _col2

Loop

 

This doesn't work

 

2. so I tried to loop through all the records in the table updating _col2 based on the value in Tablename._col1

ie

 

Fetch First from Tablename

 Do While Not EOT(Tablename)

     If (Tablename._col1<=15) Then

         Update Tablename Set _col2=_col3

         ElseIf Tablename._col1>15 and Tablename._col1<=16 Then

         Update Tablename Set _col2=(_col3-((_col3/100)*1.2))

         ElseIf Tablename._col1>16 Then

         Update Tablename Set _col2=(_col3-((_col3_col2/100)*17))

         End If

    Fetch Next From Tablename

Loop

 

This doesn't work either!

I know this must be a very simple thing to try and do - so could anyone please point me in the right direction?

 

                                Thanks,

 

                                                Jim Wilson