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how VB get data from database randomly

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Join Date: Aug 2005

Posts: 24

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bang2711

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how VB get data from database randomly

Dec 13th, 2005

hi guy,

i need this ugently.. hope someone can help me out..

i need to get data from database,
but want it to take randomly and also dont want to get data duplicate.

Ex; i get data A from DB, then there will be a next button. i wan to go next data after i click it,
and get data c, later i dont wan to get back A & C again.

i`m doing Question and Answer thing.

thanks alot..

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Join Date: Aug 2005

Posts: 24

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bang2711

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Re: how VB get data from database randomly

Dec 13th, 2005

this is my program..
please help me

Attached Files

testing.zip (419.2 KB, 79 views)

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Join Date: Nov 2005

Posts: 134

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Yomet

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Re: how VB get data from database randomly

Dec 14th, 2005

Hi Bang2711,

First of all you are missing two .dlls in your .zip file:
XVoice.dll
ExButton.dll

Next, I see you have references to both DAO and ADODB in your project, unless you actually use both (and from what I see you are only using DAO) remove the one you are not using to avoid conflicts, OR specify which type you are using,
i.e. Dim rstdb1 As DAO.Recordset OR
Dim rstdb1 As ADODB.Recordset
Otherwise VB will pick which ever one it wants to...

Now to a possible soution.

An idea come to my mind as soon as I read your post and here it is.

Create a user defined type and a public variable of that type:

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
Public Type DBWords
   DataID As Long
   Used As Boolean
End Type
 
Public DBWordsArr() As DBWords
Public Type DBWords
   DataID As Long
   Used As Boolean
End Type

Public DBWordsArr() As DBWords

You do NOT want to set a limit here since you want to be able to resize it dynamically depending on the data in your DB.

Next you load your array with the IDs from your table PicSentenses and FALSE in the boolean part.

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
Set rstdb1 = db.OpenRecordset("SELECT ID FROM PicSentenses")
rstdb1.MoveLast 'Will get an accurate RecordCount
rstdb1.MoveFirst
ReDim DBWordsArr(rstdb1.RecordCount -1) 
i = 0
'Unless you want to use a 1-based array
'ReDim DBWordsArr(1 to rstdb1.RecordCount)
'i = 1
While Not rstdb1.EOF
   DBWordsArr(i).DataID = rstdb1!ID
   DBWordsArr(i).Used = False
   rstdb1.MoveNext
   i = i + 1
Wend
'ALWAYS close your recordsets in VB otherwise you are prone to memory leaks, yes EVEN in VB...  :)
rstdb1.Close  
Set rstdb1 = Nothing
Set rstdb1 = db.OpenRecordset("SELECT ID FROM PicSentenses")
rstdb1.MoveLast 'Will get an accurate RecordCount
rstdb1.MoveFirst
ReDim DBWordsArr(rstdb1.RecordCount -1) 
i = 0
'Unless you want to use a 1-based array
'ReDim DBWordsArr(1 to rstdb1.RecordCount)
'i = 1
While Not rstdb1.EOF
   DBWordsArr(i).DataID = rstdb1!ID
   DBWordsArr(i).Used = False
   rstdb1.MoveNext
   i = i + 1
Wend
'ALWAYS close your recordsets in VB otherwise you are prone to memory leaks, yes EVEN in VB...  :)
rstdb1.Close  
Set rstdb1 = Nothing

Then you use your random code to get the next array element to use verifying for Used, I would create a function that returns a new random number within the range of subscripts of DBWordsArr

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
i = GetNextElement()
While DBWordsArr(i).Used 
   i = GetNextElement()
Wend
Set rstdb2=db.OpenRecordset("SELECT * FROM PicSentenses WHERE ID = " & DBWordsArr(i).DataID)
i = GetNextElement()
While DBWordsArr(i).Used 
   i = GetNextElement()
Wend
Set rstdb2=db.OpenRecordset("SELECT * FROM PicSentenses WHERE ID = " & DBWordsArr(i).DataID)

To guard against a infinite loop I would also keep counters of how many items I have in the array and of how many I have used so far.

Whenever you visit on node of your array you set the Used flag to TRUE and then you cannot get that item back until you have gone through the entire array and reset all the Used flags to FALSE.

Hope this makes sense and that it helps

Have fun

Yomet

P.S. I have not tested this code as I just typed it here in the answer window...