Update query (or other method) to a typed dataset

Question

Hi
i have created a typed DataSet in code that is created at runtime. It gets populated then it needs to be updated based on 2 paramaters
EmployeeID & AssignmentID
How can i run an update query on the runtime created Dataset? Hee is how i create my Dataset-
Private sGridDataSet As New DataSet("GridDataset")
Private tblGridTable As DataTable
sGridDataSet.CaseSensitive = False
tblGridTable = sGridDataSet.Tables.Add("tblGrid")
With tblGridTable
.Columns.Add("AssignmentID", GetType(System.String))
.Columns.Add("ProjectName", GetType(System.String))
.Columns.Add("Day1", GetType(System.String))
.Columns.Add("Day2", GetType(System.String))
.Columns.Add("Day3", GetType(System.String))
.Columns.Add("Day4", GetType(System.String))
.Columns.Add("Day5", GetType(System.String))
.Columns.Add("Day6", GetType(System.String))
.Columns.Add("Day7", GetType(System.String))
End With
'get data from qryAssignments
sAssignID = Me.AssignmentData.qryAssignments.Rows(j)(1)
sProjName = Me.AssignmentData.qryAssignments.Rows(j)(0)
newValues = {sAssignID, sProjName, Day1, Day2, Day3, Day4, Day5, Day6, Day7}
tblGridTable.Rows.Add(newValues)
Me.QryAssignmentsTableAdapter.ClearBeforeFill = True
Dim sDate As Date = Me.txtDate.Text
Dim EndDate As Date = sDate.AddDays(6)
Me.QryAssignmentTimesTableAdapter.Fill(Me.AssignmentData.qryAssignmentTimes, Me.txtEmployeeID.Text, Me.txtDate.Text, CStr(CType(CStr(EndDate), DateTime)))
Dim p As Integer = 0
For p = 0 To Me.AssignmentData.qryAssignmentTimes.Rows.Count - 1
vDayNo = Weekday(Me.AssignmentData.qryAssignmentTimes.Rows(p)(0), FirstDayOfWeek.Monday)
Dim m As String = Me.AssignmentData.qryAssignmentTimes.Rows(p)(0)
'NEED TO UPDATE DATASET TABLE HERE BASED ON EMPLOYEEID AND ASSIGNMENTID
Next
Me.GridControl1.DataSource = tblGridTable
Hopefully, someone can give me a few pointers :)
Thanks
Nigel
Nacho is the derivative of Nigel "True fact!"

Answer 1

Hello,
If I have more than one table to work with, a DataSet would be the container while if one table then no DataSet, just a DataTable. I would use code similar to the following which is for MS-Access yet by changing to SqlClient data provider instead of OelDb
data provider the same methods work.
Taken from
this project.
Module DatabaseOperations
Private Builder As New OleDb.OleDbConnectionStringBuilder With
.Provider = "Microsoft.ACE.OLEDB.12.0",
.DataSource = IO.Path.Combine(Application.StartupPath, "Database1.accdb")
''' <summary>
''' Read USA customers from database into a DataTable
''' </summary>
''' <returns></returns>
''' <remarks>
''' Database is assumed to be in the Bin\Debug folder.
''' </remarks>
Public Function LoadCustomers() As DataTable
Using cn As New OleDb.OleDbConnection With {.ConnectionString = Builder.ConnectionString}
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText =
<SQL>
SELECT
Identifier,
CompanyName,
ContactName,
ContactTitle,
Address,
City,
PostalCode,
Country
FROM Customer;
</SQL>.Value
Dim dt As New DataTable With {.TableName = "Customer"}
Try
cn.Open()
dt.Load(cmd.ExecuteReader)
dt.Columns("Identifier").ColumnMapping = MappingType.Hidden
dt.Columns("Country").ColumnMapping = MappingType.Hidden
Catch ex As Exception
MessageBox.Show("Failed to load customer data. See error message below" & Environment.NewLine & ex.Message)
End Try
dt.AcceptChanges()
Return dt
End Using
End Using
End Function
Public Function RemoveCurrentCustomer(ByVal Identfier As Integer) As Boolean
Try
Using cn As New OleDb.OleDbConnection With {.ConnectionString = Builder.ConnectionString}
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText = "DELETE FROM Customer WHERE Identifier = ?"
Dim IdentifierParameter As New OleDb.OleDbParameter With
.DbType = DbType.Int32,
.ParameterName = "P1",
.Value = Identfier
cmd.Parameters.Add(IdentifierParameter)
Try
cn.Open()
Dim Affected = cmd.ExecuteNonQuery
Return Affected = 1
Catch ex As Exception
Return False
End Try
End Using
End Using
Catch ex As Exception
' Handle or not handle exceptions for failed save operation
Return False
End Try
End Function
Public Function AddNewRow(ByVal Name As String, ByVal Contact As String, ByRef Identfier As Integer) As Boolean
Dim Success As Boolean = True
Try
Using cn As New OleDb.OleDbConnection With {.ConnectionString = Builder.ConnectionString}
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText =
<SQL>
INSERT INTO Customer
CompanyName,
ContactName
Values
@CompanyName,
@ContactName
</SQL>.Value
cmd.Parameters.AddWithValue("@CompanyName", Name)
cmd.Parameters.AddWithValue("@ContactName", Contact)
cn.Open()
cmd.ExecuteNonQuery()
cmd.CommandText = "Select @@Identity"
Identfier = CInt(cmd.ExecuteScalar)
End Using
End Using
Catch ex As Exception
Success = False
End Try
Return Success
End Function
Public Function SaveChanges(ByVal sender As DataRow) As Boolean
Try
Using cn As New OleDb.OleDbConnection With {.ConnectionString = Builder.ConnectionString}
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText =
<SQL>
UPDATE
Customer
SET
CompanyName=?,
ContactName=?
WHERE Identifier = ?
</SQL>.Value
Dim CompanyNameParameter As New OleDb.OleDbParameter With
.DbType = DbType.String,
.ParameterName = "P1",
.Value = sender.Field(Of String)("CompanyName")
cmd.Parameters.Add(CompanyNameParameter)
Dim ContactNameParameter As New OleDb.OleDbParameter With
.DbType = DbType.String,
.ParameterName = "P2",
.Value = sender.Field(Of String)("ContactName")
cmd.Parameters.Add(ContactNameParameter)
Dim IdentifierParameter As New OleDb.OleDbParameter With
.DbType = DbType.Int32,
.ParameterName = "P3",
.Value = sender.Field(Of Int32)("Identifier")
cmd.Parameters.Add(IdentifierParameter)
Try
cn.Open()
Dim Affected = cmd.ExecuteNonQuery
Return Affected = 1
Catch ex As Exception
Return False
End Try
End Using
End Using
Catch ex As Exception
' Handle or not handle exceptions for failed save operation
Return False
End Try
End Function
End Module
Here is an example of retrieving a row of data via a where condition
Public Sub LoadSingle(ByVal Identifier As Integer)
Using cn As New OleDb.OleDbConnection With
.ConnectionString = Builder.ConnectionString
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText =
<SQL>
SELECT
Identifier,
CompanyName,
ContactName
FROM
Customers
WHERE Identifier=@Identifier
</SQL>.Value
cmd.Parameters.Add(New OleDb.OleDbParameter With
.DbType = DbType.Int32,
.ParameterName = "@Identifier",
.Value = Identifier
cn.Open()
Dim Reader As OleDb.OleDbDataReader = cmd.ExecuteReader
If Reader.HasRows Then
Reader.Read()
Console.WriteLine("Name: {0} Contact name: {1}",
Reader.GetString(1), Reader.GetString(2))
End If
End Using
End Using
End Sub
Here you can see (using a random example) that SQL-Server code uses the same logic and methods
Using cn As New SqlConnection With {.ConnectionString = MyConnectionString}
Dim CompanySearch As String = "An"
Using cmd As New SqlCommand With {.Connection = cn}
cmd.CommandText =
<SQL>
SELECT CompanyName
FROM
Customers
WHERE
CompanyName LIKE @CompanyName
</SQL>.Value
cmd.Parameters.Add(
New SqlParameter With
.DbType = DbType.String,
.Value = CompanySearch & "%",
.ParameterName = "@CompanyName"
cn.Open()
Dim Reader = cmd.ExecuteReader
If Reader.HasRows Then
While Reader.Read
Console.WriteLine(Reader.GetString(0))
End While
Else
Console.WriteLine("No matches")
End If
End Using
End Using
So all the above is "hand coding" and there is still the option to use Adapters but for simple stuff they are over kill. The only benefit for them with simple stuff is if you are a visual person, thats it.
See also:
This article on creating SQL statement as per how I did it in the examples above. In the next release of Visual Studio this method will be easier similar to C#
Currently in C# we can do this
string selectStatement = @"
SELECT CompanyName
FROM
Customers
WHERE
CompanyName LIKE @CompanyName";
On creating a DataTable, check out this simple utility
https://code.msdn.microsoft.com/DataTable-creator-95b655b3
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