DataView vs. DataSet

  • Thread starter Thread starter Hemang Shah
  • Start date Start date
H

Hemang Shah

Hello

Few things to remove the cloud:

1) Can a DataView be a subset of a DataSet ?
2) DataSet consists of tables, is that different from a DataTable object ?
3) In IDE, when you create a DataSet it also generates update, add, delete
code, if you have controls bound to the DataView (which inturn points to
tables in the same DataSet), if you edit records / add / delete, will the
DataSet update / add / delete code still update these changes ?

Thank You
 
Glad you posted here. See how quickly you just might get an answer out of
this newsgroup ..
1) Can a DataView be a subset of a DataSet ?
Click to expand...
No, only datatable. But datatables inside a dataset, alongwith relationships
might let you acheive what you're tryin' to do.
2) DataSet consists of tables, is that different from a DataTable object
?
Click to expand...
Yes, A DataSet is a collection of Tables and Relations.
3) In IDE, when you create a DataSet it also generates update, add,
delete code, if you have controls bound to the DataView (which inturn
points to tables in the same DataSet), if you edit records / add / delete,
will the DataSet update / add / delete code still update these changes ?
Click to expand...
Yes

:-) Does that help?

- Sahil Malik
http://codebetter.com/blogs/sahil.malik/
 
Thanks for the reply Sahil yes it helps with my 3rd question, but I'm still
rusty on the first two:
1) Can a DataView be a subset of a DataSet ?
Click to expand...
No, only datatable. But datatables inside a dataset, alongwith relationships
might let you acheive what you're tryin' to do.

DataView cannot be a subset of datatable, but DataView can consist of
Datatables correct ?
2) DataSet consists of tables, is that different from a DataTable object
?
Click to expand...
Yes, A DataSet is a collection of Tables and Relations.

So how is a DataTable different from a table in a dataset ? Because we can
create a DataView object either from a datatable or a <dataset.table> so
what is the difference?

Thank You!

P.S: ADO can fetch information from an excel sheet as well right ? I'm sure
it does, just wanted a nod from u :)
 
DataView cannot be a subset of datatable, but DataView can consist of
Datatables correct ?
Click to expand...

No .. DataViews can show you a view of a DataTable .. one DataTable, not
DataTable(s).
So how is a DataTable different from a table in a dataset ? Because we
can create a DataView object either from a datatable or a <dataset.table>
so what is the difference?
Click to expand...

A dataset is .. well almost like a mini RDBMS in memory. A Datatable is just
one table of that mini rdbms.

... and Yes .. ADO can fetch information from an Excel sheet !! :) (NOD NOD).

- Sahil Malik
http://codebetter.com/blogs/sahil.malik/
 
Ok, our currencymanager is not in sync, because I'm not able to ask it
properly.

I understand the difference between tables and dataset (Thank God!)

But there are two objects: tables & DataTable - I want to know if there is
any difference between them.

When you create few dataadapter and generate dataset of them

suppose dataset ds consists of t1,t2 & t3.

Now in ADO there is a DataTable

Just by generating this dataset is t1,t2 & t3 already of type "DataTable' ?

because I've seen many codes expliciting enumerating

DataTable dtTable1 = ds.t1;

- Why would u do that when t1 is already a table ?....

I hope now my question is more lucid.
 
Tables is a collection of DataTables.
suppose dataset ds consists of t1,t2 & t3.
Just by generating this dataset is t1,t2 & t3 already of type "DataTable'
?
Yes

DataTable dtTable1 = ds.t1;
- Why would u do that when t1 is already a table ?....
Click to expand...

Well, you'd do that if you wanted to refer to the dtTable1 again and again
... so instead of writing code like ds.t1.xxx, you could say .. dtTable1.xxx


- Sahil Malik
http://codebetter.com/blogs/sahil.malik/
 
Think of a DataSet as a relational database held in memory only.

A DataSet has a Tables collection made up of DataTable objects.
A DataTable has a Columns collection made up of DataColumn objects
(equivalent to fields).
A DataTable also has a Rows collection made up of DataRow objects (records).
A DataRow has an Items collection made up of DataItems (field of a given
record).

A DataView is just that...a way of viewing existing data in a DataTable. A
DataView does not contain any data of its own. Another way of thinking
about a DataView is that it is a filtered and/or sorted look at the data in
a DataTable.

A DataSet also has a Constraints and a Relations collection to aid in using
a DataSet as a RDBMS in memory.
 
Thank You Scott

Now I know the tables generated in the dataset by IDE is automatically part
of the DataTable group (because those tables are DataTables!)

Thanks.

HS
 
Yes, but to get the terminology right:

DataTables are held in the Tables collection of a DataSet
DataRows are held in the Rows collection of a DataTable
DataColumns are held in the Columns collection of a DataTable
....ad nauseum...
 
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