G
Geoff Jones
Hi Cor
Very clever ideas! I especially like the cloning.
Thanks again
Geoff
Very clever ideas! I especially like the cloning.
Thanks again
Geoff
G
Geoff Jones
Hi Bernie
I hope I'm not putting you to too much trouble. You've been invaluable
already!
At the moment, I'm getting a list of approximately 10,000 ID's i.e. primary
keys from another process which give me the rows in the 200,000 total. As I
said previously, I was originally getting these rows by using a
Table.Rows.Find. From these 10,000 or so rows, I'm trying to filter them
down to those which satisfy a PRODUCT field criteria e.g. PRODUCT IN
('3454', '324', '7855', etc.)
Indeed, my next step may be to do something like (forgive the pseudo code):
WHERE PRODUCT = '2345' AND COST = '3.45'
where COST is another field.
I had considered the possibility of using multiple tables i.e. searching a
table for rows, creating a new table, searching this new table with a new
criteria etc. etc. in the same way that Cor has suggested. I'm interested in
both techniques i.e. cloning and SQL type coding. What are the advantages
and disadvantages of both?
Thanks again for your continuing help.
Geoff
I hope I'm not putting you to too much trouble. You've been invaluable
already!
At the moment, I'm getting a list of approximately 10,000 ID's i.e. primary
keys from another process which give me the rows in the 200,000 total. As I
said previously, I was originally getting these rows by using a
Table.Rows.Find. From these 10,000 or so rows, I'm trying to filter them
down to those which satisfy a PRODUCT field criteria e.g. PRODUCT IN
('3454', '324', '7855', etc.)
Indeed, my next step may be to do something like (forgive the pseudo code):
WHERE PRODUCT = '2345' AND COST = '3.45'
where COST is another field.
I had considered the possibility of using multiple tables i.e. searching a
table for rows, creating a new table, searching this new table with a new
criteria etc. etc. in the same way that Cor has suggested. I'm interested in
both techniques i.e. cloning and SQL type coding. What are the advantages
and disadvantages of both?
Thanks again for your continuing help.
Geoff
B
Bernie Yaeger
Hi Geoff,
Not putting me out at all; glad to help.
But I'm still confused. You originally said this:
I have a list of about 100 numbers which correspond to the ID field
and also another 40 say numbers corresponding to the numbers in the
PRODUCT field.
Now you mentioned 10000 - quite a difference.
In any event, that may not be an issue. You say now you have these 10,000
rows - in a dataset/datatable? I have a code sample below that's very fast
and might serve as a template for you. It fills a dataset and then makes a
dataview from the datatable and then filters the rows as necessary, using 2
criteria (replace these with product and cost).
Let me know if we're getting somewhere.
Regards,
Bernie
Dim oconn As New SqlConnection("data source=d5z0071;initial
catalog=imc;integrated security=sspi;")
Dim ocmd As New SqlCommand("select * from prod order by bipad", oconn)
Dim oda As New SqlDataAdapter(ocmd)
Dim ods As New DataSet("prod")
Try
oconn.Open()
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
oda.Fill(ods, "prod")
Dim vue As New DataView(ods.Tables(0))
vue.Sort = "bipad"
vue.RowFilter = "bipad in ('18772','18770','01043') and issuecode =
'200304'"
Dim irow As DataRow
Dim irows As DataRow()
Dim i As Integer
For i = 0 To vue.Count - 1
MessageBox.Show(vue(i)("bipad"))
MessageBox.Show(vue(i)("issuecode"))
MessageBox.Show(vue(i)("usprice"))
Next
oconn.Close()
Not putting me out at all; glad to help.
But I'm still confused. You originally said this:
I have a list of about 100 numbers which correspond to the ID field
and also another 40 say numbers corresponding to the numbers in the
PRODUCT field.
Now you mentioned 10000 - quite a difference.
In any event, that may not be an issue. You say now you have these 10,000
rows - in a dataset/datatable? I have a code sample below that's very fast
and might serve as a template for you. It fills a dataset and then makes a
dataview from the datatable and then filters the rows as necessary, using 2
criteria (replace these with product and cost).
Let me know if we're getting somewhere.
Regards,
Bernie
Dim oconn As New SqlConnection("data source=d5z0071;initial
catalog=imc;integrated security=sspi;")
Dim ocmd As New SqlCommand("select * from prod order by bipad", oconn)
Dim oda As New SqlDataAdapter(ocmd)
Dim ods As New DataSet("prod")
Try
oconn.Open()
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
oda.Fill(ods, "prod")
Dim vue As New DataView(ods.Tables(0))
vue.Sort = "bipad"
vue.RowFilter = "bipad in ('18772','18770','01043') and issuecode =
'200304'"
Dim irow As DataRow
Dim irows As DataRow()
Dim i As Integer
For i = 0 To vue.Count - 1
MessageBox.Show(vue(i)("bipad"))
MessageBox.Show(vue(i)("issuecode"))
MessageBox.Show(vue(i)("usprice"))
Next
oconn.Close()
G
Geoff Jones
Hiya Bernie
The difference i.e. 100 as opposed to 10000 was merely the range of
possibilities. Sorry for the confusion.
The rows are in a DataSet; but also in a table - which is stored in the
DataSet.
The code looks excellent. I'll give it a try tomorrow.
Geoff
The difference i.e. 100 as opposed to 10000 was merely the range of
possibilities. Sorry for the confusion.
The rows are in a DataSet; but also in a table - which is stored in the
DataSet.
The code looks excellent. I'll give it a try tomorrow.
Geoff
G
Geoff Jones
HI Bernie
Thanks for the code. I've learned a lot in the last few days with your and
others help. I do like the idea of using "IN" but unfortunately it does seem
to be slower than my original idea. I've written some code based on Cor's
which demonstrates the difference:
The first bit of code filters the dataset using "IN" and the last bit does
it using a "Find". When I ran it this morning, the SQL code took 41 seconds
whilst the Find took 0.03 seconds. Quite a difference.
Obviously, I couldn't use the same technique i.e. "Find", from the outset,
using a non-primary key (because it needs a primary key to work).
Maybe the best approach is a mixture of both techniques?
Geoff
P.S. Code is below:
Dim dt As New DataTable
Private Sub Form1_Load(ByVal sender _
As System.Object, ByVal e As System.EventArgs) _
Handles MyBase.Load
dt.Columns.Add("ID")
dt.Columns.Add("PRODUCT")
dt.Columns.Add("COST")
For i As Integer = 0 To 200000
dt.Rows.Add(dt.NewRow)
dt.Rows(i)(0) = i.ToString
Dim rg As Random = New Random(i)
Dim rn As Integer = CInt(rg.Next(0, 200000))
dt.Rows(i)(1) = rn.ToString
rg = New Random(rn)
rn = CInt(rg.Next(0, 200000))
dt.Rows(i)(2) = rn.ToString
Next
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim start As DateTime = DateTime.Now
Dim numOfRows As Integer = dt.Rows.Count
Dim vue As DataView = New DataView(dt)
vue.Sort = "ID"
vue.RowFilter = "ID IN
('139211','139215','139214','139213','139212','139211','139210','139259','139258','139257','139251','139255','139254','139253','139252','139251','139250','139249','139248','139247','139241','139245','139244','139243','139242','139241','139240','139239','139238','139237','139231','139235','139234','139233','139232','139231','139230','139229','139228','139227','139221','139225','139224','139223','139222','139221','139220','139219','139218','139217','139211','139215','139214','139213','139212','139211','139210','139209','139208','139207','139201','139205','139204','139203','139202','139201','139200','139199','139198','139197','139191','139195','139194','139193','139192','139191','139190','139189','139188','139187','139181','139185','139184','139183','139182','139181','139180','139179','139178','139177','139171','139175','139174','139173','139172','139171','139170','139119','139118','139117','139111','139115','139114','139113','139112','139111','139110','139159','139158','139157','139151','139155','139154','139153','139152','139151','139150','139149','139148','139147','139141','139145','139144','139143','139142','139141','139140','139139','139138','139137','139131','139135','139134','139133','139132','139131','139130','139129','139128','139127','139121','139125','139124','139123','139122','139121','139120','139119','139118','139117','139111','139115','139114','139113','139112','139111','139110','139109','139108','139107','139101','139105','139104','139103','139102','139101','139100','139099','139098','139097','139091','139095','139094','139093','139092','139091','139090','139089','139088','139087','139081','139085','139084','139083','139082','139081','139080','139079','139078','139077','139071','139075','139074','139073','139072','139071','139070','139019','139018','139017','139011','139015','139014','139013','139012','139011','139010','139059','139058','139057','139051','139055','139054','139053','139052','139051','139050','139049','139048','139047','139041','139045','139044','139043','139042','139041','139040','139039','139038','139037','139031','139035','139034','139033','139032','139031','139030','139029','139028','139027','139021','139025','139024','139023','139022','139021','139020','139019','139018','139017','139011','139015','139014','139013','139012','139011','139010','139009','139008','139007','139001','139005','139004','139003','139002','139001','139000','138999','138998','138997','138991','138995','138994','138993','138992','138991','138990','138989','138988','138987','138981','138985','138984','138983','138982','138981','138980','138979','138978','138977','138971','138975','138974','138973','138972','139275','139274','139273','139272','139271','139270','139219','139218','139217')"
DataGrid1.DataSource = dt
Dim finish As DateTime = DateTime.Now
Dim time As TimeSpan = finish.Subtract(start)
Debug.WriteLine("Time taken = " & time.TotalSeconds)
DataGrid1.DataSource = dt
dt.PrimaryKey = New DataColumn() {dt.Columns("ID")}
start = DateTime.Now
Dim newTable As DataTable = dt.Clone
Dim str1() As String = {"139211", "139215", "139214", "139213", "139212",
"139211", "139210", "139259", "139258", "139257", "139251", "139255",
"139254", "139253", "139252", "139251", "139250", "139249", "139248",
"139247", "139241", "139245", "139244", "139243", "139242", "139241",
"139240", "139239", "139238", "139237", "139231", "139235", "139234",
"139233", "139232", "139231", "139230", "139229", "139228", "139227",
"139221", "139225", "139224", "139223", "139222", "139221", "139220",
"139219", "139218", "139217", "139211", "139215", "139214", "139213",
"139212", "139211", "139210", "139209", "139208", "139207", "139201",
"139205", "139204", "139203", "139202", "139201", "139200", "139199",
"139198", "139197", "139191", "139195", "139194", "139193", "139192",
"139191", "139190", "139189", "139188", "139187", "139181", "139185",
"139184", "139183", "139182", "139181", "139180", "139179", "139178",
"139177", "139171", "139175", "139174", "139173", "139172", "139171",
"139170", "139119", "139118", "139117", "139111", "139115", "139114",
"139113", "139112", "139111", "139110", "139159", "139158", "139157",
"139151", "139155", "139154", "139153", "139152", "139151", "139150",
"139149", "139148", "139147", "139141", "139145", "139144", "139143",
"139142", "139141", "139140", "139139", "139138", "139137", "139131",
"139135", "139134", "139133", "139132", "139131", "139130", "139129",
"139128", "139127", "139121", "139125", "139124", "139123", "139122",
"139121", "139120", "139119", "139118", "139117", "139111", "139115",
"139114", "139113", "139112", "139111", "139110", "139109", "139108",
"139107", "139101", "139105", "139104", "139103", "139102", "139101",
"139100", "139099", "139098", "139097", "139091", "139095", "139094",
"139093", "139092", "139091", "139090", "139089", "139088", "139087",
"139081", "139085", "139084", "139083", "139082", "139081", "139080",
"139079", "139078", "139077", "139071", "139075", "139074", "139073",
"139072", "139071", "139070", "139019", "139018", "139017", "139011",
"139015", "139014", "139013", "139012", "139011", "139010", "139059",
"139058", "139057", "139051", "139055", "139054", "139053", "139052",
"139051", "139050", "139049", "139048", "139047", "139041", "139045",
"139044", "139043", "139042", "139041", "139040", "139039", "139038",
"139037", "139031", "139035", "139034", "139033", "139032", "139031",
"139030", "139029", "139028", "139027", "139021", "139025", "139024",
"139023", "139022", "139021", "139020", "139019", "139018", "139017",
"139011", "139015", "139014", "139013", "139012", "139011", "139010",
"139009", "139008", "139007", "139001", "139005", "139004", "139003",
"139002", "139001", "139000", "138999", "138998", "138997", "138991",
"138995", "138994", "138993", "138992", "138991", "138990", "138989",
"138988", "138987", "138981", "138985", "138984", "138983", "138982",
"138981", "138980", "138979", "138978", "138977", "138971", "138975",
"138974", "138973", "138972", "139275", "139274", "139273", "139272",
"139271", "139270", "139219", "139218", "139217"}
For Each st As String In str1
Dim row As DataRow = dt.Rows.Find(st)
If newTable.Rows.Find(st) Is Nothing Then
newTable.ImportRow(row)
End If
Next
finish = DateTime.Now
time = finish.Subtract(start)
Debug.WriteLine("Time taken = " & time.TotalSeconds)
DataGrid1.DataSource = newTable
End Sub
Thanks for the code. I've learned a lot in the last few days with your and
others help. I do like the idea of using "IN" but unfortunately it does seem
to be slower than my original idea. I've written some code based on Cor's
which demonstrates the difference:
The first bit of code filters the dataset using "IN" and the last bit does
it using a "Find". When I ran it this morning, the SQL code took 41 seconds
whilst the Find took 0.03 seconds. Quite a difference.
Obviously, I couldn't use the same technique i.e. "Find", from the outset,
using a non-primary key (because it needs a primary key to work).
Maybe the best approach is a mixture of both techniques?
Geoff
P.S. Code is below:
Dim dt As New DataTable
Private Sub Form1_Load(ByVal sender _
As System.Object, ByVal e As System.EventArgs) _
Handles MyBase.Load
dt.Columns.Add("ID")
dt.Columns.Add("PRODUCT")
dt.Columns.Add("COST")
For i As Integer = 0 To 200000
dt.Rows.Add(dt.NewRow)
dt.Rows(i)(0) = i.ToString
Dim rg As Random = New Random(i)
Dim rn As Integer = CInt(rg.Next(0, 200000))
dt.Rows(i)(1) = rn.ToString
rg = New Random(rn)
rn = CInt(rg.Next(0, 200000))
dt.Rows(i)(2) = rn.ToString
Next
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim start As DateTime = DateTime.Now
Dim numOfRows As Integer = dt.Rows.Count
Dim vue As DataView = New DataView(dt)
vue.Sort = "ID"
vue.RowFilter = "ID IN
('139211','139215','139214','139213','139212','139211','139210','139259','139258','139257','139251','139255','139254','139253','139252','139251','139250','139249','139248','139247','139241','139245','139244','139243','139242','139241','139240','139239','139238','139237','139231','139235','139234','139233','139232','139231','139230','139229','139228','139227','139221','139225','139224','139223','139222','139221','139220','139219','139218','139217','139211','139215','139214','139213','139212','139211','139210','139209','139208','139207','139201','139205','139204','139203','139202','139201','139200','139199','139198','139197','139191','139195','139194','139193','139192','139191','139190','139189','139188','139187','139181','139185','139184','139183','139182','139181','139180','139179','139178','139177','139171','139175','139174','139173','139172','139171','139170','139119','139118','139117','139111','139115','139114','139113','139112','139111','139110','139159','139158','139157','139151','139155','139154','139153','139152','139151','139150','139149','139148','139147','139141','139145','139144','139143','139142','139141','139140','139139','139138','139137','139131','139135','139134','139133','139132','139131','139130','139129','139128','139127','139121','139125','139124','139123','139122','139121','139120','139119','139118','139117','139111','139115','139114','139113','139112','139111','139110','139109','139108','139107','139101','139105','139104','139103','139102','139101','139100','139099','139098','139097','139091','139095','139094','139093','139092','139091','139090','139089','139088','139087','139081','139085','139084','139083','139082','139081','139080','139079','139078','139077','139071','139075','139074','139073','139072','139071','139070','139019','139018','139017','139011','139015','139014','139013','139012','139011','139010','139059','139058','139057','139051','139055','139054','139053','139052','139051','139050','139049','139048','139047','139041','139045','139044','139043','139042','139041','139040','139039','139038','139037','139031','139035','139034','139033','139032','139031','139030','139029','139028','139027','139021','139025','139024','139023','139022','139021','139020','139019','139018','139017','139011','139015','139014','139013','139012','139011','139010','139009','139008','139007','139001','139005','139004','139003','139002','139001','139000','138999','138998','138997','138991','138995','138994','138993','138992','138991','138990','138989','138988','138987','138981','138985','138984','138983','138982','138981','138980','138979','138978','138977','138971','138975','138974','138973','138972','139275','139274','139273','139272','139271','139270','139219','139218','139217')"
DataGrid1.DataSource = dt
Dim finish As DateTime = DateTime.Now
Dim time As TimeSpan = finish.Subtract(start)
Debug.WriteLine("Time taken = " & time.TotalSeconds)
DataGrid1.DataSource = dt
dt.PrimaryKey = New DataColumn() {dt.Columns("ID")}
start = DateTime.Now
Dim newTable As DataTable = dt.Clone
Dim str1() As String = {"139211", "139215", "139214", "139213", "139212",
"139211", "139210", "139259", "139258", "139257", "139251", "139255",
"139254", "139253", "139252", "139251", "139250", "139249", "139248",
"139247", "139241", "139245", "139244", "139243", "139242", "139241",
"139240", "139239", "139238", "139237", "139231", "139235", "139234",
"139233", "139232", "139231", "139230", "139229", "139228", "139227",
"139221", "139225", "139224", "139223", "139222", "139221", "139220",
"139219", "139218", "139217", "139211", "139215", "139214", "139213",
"139212", "139211", "139210", "139209", "139208", "139207", "139201",
"139205", "139204", "139203", "139202", "139201", "139200", "139199",
"139198", "139197", "139191", "139195", "139194", "139193", "139192",
"139191", "139190", "139189", "139188", "139187", "139181", "139185",
"139184", "139183", "139182", "139181", "139180", "139179", "139178",
"139177", "139171", "139175", "139174", "139173", "139172", "139171",
"139170", "139119", "139118", "139117", "139111", "139115", "139114",
"139113", "139112", "139111", "139110", "139159", "139158", "139157",
"139151", "139155", "139154", "139153", "139152", "139151", "139150",
"139149", "139148", "139147", "139141", "139145", "139144", "139143",
"139142", "139141", "139140", "139139", "139138", "139137", "139131",
"139135", "139134", "139133", "139132", "139131", "139130", "139129",
"139128", "139127", "139121", "139125", "139124", "139123", "139122",
"139121", "139120", "139119", "139118", "139117", "139111", "139115",
"139114", "139113", "139112", "139111", "139110", "139109", "139108",
"139107", "139101", "139105", "139104", "139103", "139102", "139101",
"139100", "139099", "139098", "139097", "139091", "139095", "139094",
"139093", "139092", "139091", "139090", "139089", "139088", "139087",
"139081", "139085", "139084", "139083", "139082", "139081", "139080",
"139079", "139078", "139077", "139071", "139075", "139074", "139073",
"139072", "139071", "139070", "139019", "139018", "139017", "139011",
"139015", "139014", "139013", "139012", "139011", "139010", "139059",
"139058", "139057", "139051", "139055", "139054", "139053", "139052",
"139051", "139050", "139049", "139048", "139047", "139041", "139045",
"139044", "139043", "139042", "139041", "139040", "139039", "139038",
"139037", "139031", "139035", "139034", "139033", "139032", "139031",
"139030", "139029", "139028", "139027", "139021", "139025", "139024",
"139023", "139022", "139021", "139020", "139019", "139018", "139017",
"139011", "139015", "139014", "139013", "139012", "139011", "139010",
"139009", "139008", "139007", "139001", "139005", "139004", "139003",
"139002", "139001", "139000", "138999", "138998", "138997", "138991",
"138995", "138994", "138993", "138992", "138991", "138990", "138989",
"138988", "138987", "138981", "138985", "138984", "138983", "138982",
"138981", "138980", "138979", "138978", "138977", "138971", "138975",
"138974", "138973", "138972", "139275", "139274", "139273", "139272",
"139271", "139270", "139219", "139218", "139217"}
For Each st As String In str1
Dim row As DataRow = dt.Rows.Find(st)
If newTable.Rows.Find(st) Is Nothing Then
newTable.ImportRow(row)
End If
Next
finish = DateTime.Now
time = finish.Subtract(start)
Debug.WriteLine("Time taken = " & time.TotalSeconds)
DataGrid1.DataSource = newTable
End Sub
B
Bernie Yaeger
Hi Goeff,
You are correct; Cor's approach is much faster.
Good luck,
Bernie
You are correct; Cor's approach is much faster.
Good luck,
Bernie
J
Jay B. Harlow [MVP - Outlook]
Geoff,
You should be able to use DataView.Find or DataView.FindRows on non-primary
keys with about the same performance as DataRowCollection.Find.
When you create the DataView, set the DataView.Sort property to the
non-primary key columns you are searching on, do not need to set the
RowFilter property.
Then rather then using DataTable.Rows.Find, use DataView.Find or
DataView.FindRows! DataView.Find returns an integer index into the DataView,
while DataView.FindRows returns DataRowView objects...
Something like:
dt.PrimaryKey = Nothing
Dim newTable As DataTable = dt.Clone
newTable.PrimaryKey = New DataColumn() {newTable.Columns("ID")}
Dim view As New DataView(dt)
view.Sort = "ID"
For Each key As String In str1
For Each row As DataRowView In view.FindRows(key)
If Not newTable.Rows.Contains(key) Then
newTable.ImportRow(row.Row)
End If
Next
Next
I don't believe the newTable.Rows.Contains is really needed. I left it in as
you had it in your original code.
Hope this helps
Jay
Actually you could have!
You should be able to use DataView.Find or DataView.FindRows on non-primary
keys with about the same performance as DataRowCollection.Find.
When you create the DataView, set the DataView.Sort property to the
non-primary key columns you are searching on, do not need to set the
RowFilter property.
Then rather then using DataTable.Rows.Find, use DataView.Find or
DataView.FindRows! DataView.Find returns an integer index into the DataView,
while DataView.FindRows returns DataRowView objects...
Something like:
dt.PrimaryKey = Nothing
Dim newTable As DataTable = dt.Clone
newTable.PrimaryKey = New DataColumn() {newTable.Columns("ID")}
Dim view As New DataView(dt)
view.Sort = "ID"
For Each key As String In str1
For Each row As DataRowView In view.FindRows(key)
If Not newTable.Rows.Contains(key) Then
newTable.ImportRow(row.Row)
End If
Next
Next
I don't believe the newTable.Rows.Contains is really needed. I left it in as
you had it in your original code.
Hope this helps
Jay
G
Geoff Jones
Hi Bernie and Jay
Many thanks for all your help. As always it has been very invaluable to
learn from you guys.
Jay - the reason I used Contains was because otherwise I got an error saying
that the row already existed. If you comment it out, you'll see that it
causes an exception in the code I posted.
Geoff
Many thanks for all your help. As always it has been very invaluable to
learn from you guys.
Jay - the reason I used Contains was because otherwise I got an error saying
that the row already existed. If you comment it out, you'll see that it
causes an exception in the code I posted.
Geoff
J
Jay B. Harlow [MVP - Outlook]
Geoff,
The values in your keys array (str1) are not unique, hence the duplicates...
I would consider ensuring that your keys array is distinct before creating
the newTable. Alternatively I would only process unique values in str1 (by
sorting it first)...
Array.Sort(str1)
Dim lastkey As String = Nothing
For Each key As String In str1
If key <> lastkey Then
For Each row As DataRowView In view.FindRows(key)
newTable.ImportRow(row.Row)
Next
lastkey = key
End If
Next
However! I am not saying using Contains is a bad thing either
Which
method to use would require profiling to decide, naturally it may change
over the life of your program.
Of course if you can ensure that your keys array is unique to begin with,
then that might be "best"...
Hope this helps
Jay
The values in your keys array (str1) are not unique, hence the duplicates...
I would consider ensuring that your keys array is distinct before creating
the newTable. Alternatively I would only process unique values in str1 (by
sorting it first)...
Array.Sort(str1)
Dim lastkey As String = Nothing
For Each key As String In str1
If key <> lastkey Then
For Each row As DataRowView In view.FindRows(key)
newTable.ImportRow(row.Row)
Next
lastkey = key
End If
Next
However! I am not saying using Contains is a bad thing either
Whichmethod to use would require profiling to decide, naturally it may change
over the life of your program.
Of course if you can ensure that your keys array is unique to begin with,
then that might be "best"...
Hope this helps
Jay
<<snip>>Geoff Jones said:
C
Cor Ligthert
Bernie,
I have the idea that you did not understand why my first message was for in
this thread and why it was so slow with the first attempts of Geoff.
There is no dataview *select* function.
What probably (that deep did I not look for it) is happening in the mix from
Geoff and your first code, (it is not that consistent that I know where it
is) is that there is created a dataview (defaultview) with a rowfilter.
That is a rowfilter for a datatable that is referenced in that dataview.
So when you filter 100 rows you can loop through that very fast.
However, when you use this.
Dataview.table.select you are selecting again from that datatable from
200.000 rows.
Therefore I showed it with that cloned and copied table.
I hope this makes it more clear why I wrote this in this thread.
Cor
I have the idea that you did not understand why my first message was for in
this thread and why it was so slow with the first attempts of Geoff.
There is no dataview *select* function.
What probably (that deep did I not look for it) is happening in the mix from
Geoff and your first code, (it is not that consistent that I know where it
is) is that there is created a dataview (defaultview) with a rowfilter.
That is a rowfilter for a datatable that is referenced in that dataview.
So when you filter 100 rows you can loop through that very fast.
However, when you use this.
Dataview.table.select you are selecting again from that datatable from
200.000 rows.
Therefore I showed it with that cloned and copied table.
I hope this makes it more clear why I wrote this in this thread.
Cor
G
Geoff Jones
Hi Jay
Good advice as always.
You mention "profiling". Is this some way of deciding which routines are the
quickest? If so, I'd be most interested in knowing how the experts do this!
I, in my naive way, have probably been doing it the slow way i.e. I wrap a
routine in between two time variables and use TimeSpan to work out how many
seconds has passed. Is there an easier way to do this using the Visual
Studio environment?
Geoff
Good advice as always.
You mention "profiling". Is this some way of deciding which routines are the
quickest? If so, I'd be most interested in knowing how the experts do this!
I, in my naive way, have probably been doing it the slow way i.e. I wrap a
routine in between two time variables and use TimeSpan to work out how many
seconds has passed. Is there an easier way to do this using the Visual
Studio environment?
Geoff
B
Bernie Yaeger
Hi Cor,
It is more clear to me now and I do understand that the 'double' select is
the cause of the delay.
Tx,
Bernie
It is more clear to me now and I do understand that the 'double' select is
the cause of the delay.
Tx,
Bernie
J
Jay B. Harlow [MVP - Outlook]
Geoff,
For more specific profiling I use CLR Profiler (or other similiar tools).
Just Remember the 80/20 rule. That is 80% of the execution time of your
program is spent in 20% of your code. I will optimize (worry about
performance, memory consumption) the 20% once that 20% has been identified &
proven to be a performance problem via profiling (CLR Profiler is one
profiling tool).
For info on the 80/20 rule & optimizing only the 20% see Martin Fowler's
article "Yet Another Optimization Article" at
http://martinfowler.com/ieeeSoftware/yetOptimization.pdf
Info on the CLR Profiler:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag/html/scalenethowto13.asp
http://msdn.microsoft.com/library/d...y/en-us/dndotnet/html/highperfmanagedapps.asp
Hope this helps
Jay
For general stuff like this that is how I normally do it.
For more specific profiling I use CLR Profiler (or other similiar tools).
Just Remember the 80/20 rule. That is 80% of the execution time of your
program is spent in 20% of your code. I will optimize (worry about
performance, memory consumption) the 20% once that 20% has been identified &
proven to be a performance problem via profiling (CLR Profiler is one
profiling tool).
For info on the 80/20 rule & optimizing only the 20% see Martin Fowler's
article "Yet Another Optimization Article" at
http://martinfowler.com/ieeeSoftware/yetOptimization.pdf
Info on the CLR Profiler:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag/html/scalenethowto13.asp
http://msdn.microsoft.com/library/d...y/en-us/dndotnet/html/highperfmanagedapps.asp
Hope this helps
Jay
G
Geoff Jones
Excellent. Thanks Jay
Geoff
Geoff
Jay B. Harlow said: