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Editing rows in a dataset is quite straight forward
once you've done it a few times.
First you need to declare a row.
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Dim CustomerRow() As
Data.DataRow |
Notice the lack of the 'new' keyword
here. We are not creating a new row, just creating a reference to a row which in
a minute will equal the row we want to edit.
Now make that row equal the row we want to edit.
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CustomerRow = ds.Tables("Customers").find("1") |
This sets the row
to equal the row in the "Customers" table in the dataset that has a primary key
equal to "1".
Notice that in the test database
the data type for the primary key column is set to text, hence why
the value is enclosed in quotes which signifies a string (text).
Now that we have
a reference to the row in our dataset that we want to edit we can start to change
its values, for example..
CustomerRow(0)("first_name") = "Florance"
CustomerRow(0)("Last_name") =
"Smith" |
And lastly, and very importantly
we need to call the 'Endedit' method of the row.
This signifies that we have finished
editing the row and that it is ready to be written back to the database.
We'll cover applying these to the
database in a minute.
Editing
the data in a dataset - Deleting rows
This is quite similar to the above
up to a point, and again we first create a reference to a data row.
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Dim CustomerRow() As
Data.DataRow |
And again we make it equal the row
we are looking for
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CustomerRow = ds.Tables("Customers").find("1") |
But now we have to do something different.
This calls the delete method on the
data row and marks it for deletion in the dataset.
Then again we must call the Endedit
method on the row
Editing
the data in a dataset - Adding new rows
Once more we need to create a new
row, but this time we do it slightly differently..
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Dim
newrow As Data.DataRow = ds.Tables("Customers").NewRow |
This creates a new data row called
newrow and makes it equal to a new row in the 'Customers' table in our ds dataset.
Now we can fill in some of the fields
in the new row..
This will set the first field of
the new row to equal '2'.
Alternately you can fill in the fields
by specifying the name of each field like this..
Once you have populated all the fields
you then need to add the new row to the dataset.
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ds.Tables("Customers").Rows.add(newrow) |
And last but not least, the ever
important...
Next we'll show you how to apply
the changes in the dataset back to the live database..
Part 4 :
Applying changes
Part 2 :
Creating a dataset and data adapter
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