Index on DataTable ?

[fniles]

Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.

Dim DT As New DataTable

DT.Columns.Add("Price", GetType(System.Int32))
DT.Columns.Add("ID", GetType(System.Int32))
DT.Columns.Add("Vol", GetType(System.Int32))

Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChanges()

 

[Kerry Moorman]

fniles,

No, I don't believe you can add an index to a datatable.

Keep in mind that datasets/datatables are not the same as an in-memory sql
database and trying to treat them as such will only lead to frustration.

Having said that, if you need an index for performance while selecting, you
might look into the dataview and its find methods. It will index on whatever
you set as its sort column.

Kerry Moorman

 

[Brian Gideon]

Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.

Dim DT As New DataTable

DT.Columns.Add("Price", GetType(System.Int32))
DT.Columns.Add("ID", GetType(System.Int32))
DT.Columns.Add("Vol", GetType(System.Int32))

Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChanges()

Not really. One exception is the PK which is indexed.

 

[fniles]

Thank you
How can you create PK on the dataTable ?

Can I create an index on a DataTable ?
On the following DataTable, I would like to create index on "Price", can I
do that ?
Thank you.

Dim DT As New DataTable

DT.Columns.Add("Price", GetType(System.Int32))
DT.Columns.Add("ID", GetType(System.Int32))
DT.Columns.Add("Vol", GetType(System.Int32))

Dim r As DataRow = DT.NewRow
r.Item(0) = 99
r.Item(1) = 1234
r.Item(2) = 350
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 98
r.Item(1) = 1233
r.Item(2) = 300
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 97
r.Item(1) = 1230
r.Item(2) = 375
r.Item(3) = 1
DT.Rows.Add(r)

r = DT.NewRow
r.Item(0) = 96
r.Item(1) = 1231
r.Item(2) = 250
r.Item(3) = 1
DT.Rows.Add(r)
DT.AcceptChanges()

Not really. One exception is the PK which is indexed.