How to edit and delete rows of a database using ASP? - sql

Question

I currently have a website that displays all the data within the database
Dim dcSQL As New SqlClient.SqlConnection(ConfigurationManager.ConnectionStrings("College").ConnectionString)
Dim dbAdapt As New System.Data.SqlClient.SqlDataAdapter()
Dim cmd As New SqlCommand("SELECT * FROM [College].[dbo].[Class]", dcSQL)
dbAdapt.SelectCommand = cmd
Dim ds As New DataSet
dbAdapt.Fill(ds)
If dbAdapt IsNot Nothing Then
gvStudents0.DataSource = ds.Tables(0)
gvStudents0.DataBind()
End If
Catch ex As Exception
End Try
End Sub'
But I want to create/edit and delete the database, I am aware of how to do this in EF but I am currently not aware in SQL, can someone help?

Answer 1

The following snippet is from SqlCommand.Parameters Property .
Updating
Dim commandText As String = _
"UPDATE Sales.Store SET Demographics = #demographics " _
& "WHERE CustomerID = #ID;"
Using connection As New SqlConnection(connectionString)
Dim command As New SqlCommand(commandText, connection)
' Add CustomerID parameter for WHERE clause.
command.Parameters.Add("#ID", SqlDbType.Int)
command.Parameters("#ID").Value = customerID
' Use AddWithValue to assign Demographics.
' SQL Server will implicitly convert strings into XML.
command.Parameters.AddWithValue("#demographics", demoXml)
Try
connection.Open()
Dim rowsAffected As Integer = command.ExecuteNonQuery()
Console.WriteLine("RowsAffected: {0}", rowsAffected)
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
End Using
Deleting
For deleting the command could be as follows.
Dim commandText As String = _
"DELETE FROM Sales.Store WHERE CustomerID = #ID;"
(...)
command.Parameters.Add("#CustomerID ", SqlDbType.Int).Value = xxx;
Inserting
For inserting the sql will be something like the following
Dim commandText As String = _
"INSERT INTO tablename(column1,column2,column3)" _
& " VALUES(#column1,#column2,#column3);"
and then
command.Parameters.Add("#column1", SqlDbType.Int).Value = x;
command.Parameters.Add("#column2", SqlDbType.Int).Value = y;
command.Parameters.Add("#column3", SqlDbType.Int).Value = z;
or
command.Parameters.AddWithValue("#column1", x);
command.Parameters.AddWithValue("#column2", y);
command.Parameters.AddWithValue("#column3", z)
Please note that this is not ASP.NET specific. A console app could use this code as well.

Answer 2

You can use this class that I make and don’t care about SQL (in some cases).
You can just pas lists (Of String) as parameter and the methods do the tasks.
Imports System.Data.SqlClient
Friend Class SqlDB
Friend Property _SConessione As String = ""
Private _NomeDB As String = ""
Private _SQLConnection As SqlConnection
Private _SQLCommand As SqlCommand
Private _SQLAdapter As SqlDataAdapter
Private _SQLReader As SqlDataReader
Friend Enum Version
SQL_SERV_2005 = 90
SQL_SERV_2008 = 100
SQL_SERV_2012 = 110
End Enum
Friend Structure Inputs
Const _CHAR As String = "CHAR"
Const _VARCHAR As String = "VARCHAR"
Const _TEXT As String = "TEXT"
Const _NCHAR As String = "NCHAR"
Const _NVARCHAR As String = "NVARCHAR"
Const _NTEXT As String = "NTEXT"
Const _BIT As String = "BIT"
Const _BINARY As String = "BINARY"
Const _VARBINARY As String = "VARBINARY"
Const _IMAGE As String = "IMAGE"
Const _TINYINT As String = "TINYINT"
Const _SMALLINT As String = "SMALLINT"
Const _BIGINT As String = "BIGINT"
Const _DECIMAL As String = "DECIMAL(10,2)"
Const _NUMERIC As String = "NUMERIC(10)"
Const _FLOAT As String = "FLOAT"
Const _DATE As String = "DATE"
Const _DATETIME As String = "DATETIME"
End Structure
Friend Structure NULLS
Const NULL = "NULL"
Const NOT_NULL = "NOT NULL"
End Structure
Friend Structure Cols
Dim Nome As String
Dim TInput As String
Dim Length As Integer
Dim Null As String
End Structure
Private _Versione As Version = Version.SQL_SERV_2008
Friend Function SqlDate(dateStr As String) As String
If IsDate(dateStr) Then
Dim sDate As String = ""
dateStr = CDate(dateStr).ToShortDateString
sDate = " CONVERT(DATE, '" & dateStr & "', 0) "
Return sDate
Else
Throw New Exception("Formato data non valido")
End If
Return ""
End Function
Friend Property Versione As Version
Get
Return _Versione
End Get
Set(value As Version)
_Versione = value
End Set
End Property
Friend Enum TypeIndex
CLUSTER = 0
NONCOLUSTER = 1
End Enum
Friend Sub New(ByVal ConString As String,
ByVal VersionServer As Version)
Try
Versione = VersionServer
If ConString.Length > 0 Then
_SConessione = ConString
End If
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
End Sub
Friend Sub New(ByVal ConString As String)
Try
Versione = _Versione
If ConString.Length > 0 Then
_SConessione = ConString
End If
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
End Sub
Friend Function ExecuteRestore(Optional ByVal pathBackup As String = "", Optional NameDb As String = "") As Boolean
Dim res As Boolean = False
If NameDb.Length > 0 Then _NomeDB = NameDb
If _NomeDB.Length = 0 Then
Debug.WriteLine("Set the name of DB")
Return False
End If
Dim Sql = " USE [master]; " & vbCrLf
Sql &= " RESTORE DATABASE [" & _NomeDB & "]" & vbCrLf
Sql &= " FROM DISK = '" & pathBackup & "'" & vbCrLf
Sql &= " WITH FILE = 1, NOUNLOAD, REPLACE" & vbCrLf '
Try
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(Sql, SQLConnection)
res = CBool(command.ExecuteNonQuery())
res = True
End Using
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return res
End Function
Friend Function ExecuteQuery(sql As String) As Boolean
Dim res As Boolean = False
If sql.Length > 0 Then
sql = "USE [" & _NomeDB & "]; " & vbCrLf & sql
End If
Try
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(sql, SQLConnection)
command.ExecuteNonQuery()
End Using
Return True
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return res
End Function
Friend Function ReadTheFirstResult(sql As String) As Object
Dim sRet As Object = ""
If sql.Length > 0 Then
sql = "USE [" & _NomeDB & "]; " & vbCrLf & sql
End If
Try
Dim SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(sql, SQLConnection)
Dim reader As SqlDataReader = command.ExecuteReader()
While reader.Read
sRet = reader(0)
Exit While
End While
Catch ex As SqlException
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return sRet
End Function
Friend Function GetDataAsDataReader(Sql As String, Optional ByRef RowsCount As Integer = -1) As SqlDataReader
Dim reader As SqlDataReader = Nothing
If Sql.Length > 0 Then
Sql = "USE [" & _NomeDB & "]; " & vbCrLf & Sql
End If
Try
Dim SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
If RowsCount > -1 Then
Dim DtTable As New DataTable
Dim mSqlAdapter As New SqlClient.SqlDataAdapter With {
.SelectCommand = New SqlCommand(Sql, SQLConnection)
}
mSqlAdapter.Fill(DtTable)
RowsCount = DtTable.Rows.Count
End If
Dim command As New SqlCommand(Sql, SQLConnection)
reader = command.ExecuteReader()
Catch ex As SqlException
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return reader
End Function
Friend Function CheckOrCreateDB(ByVal dbName As String) As Boolean
Try
Dim query As StringBuilder = New StringBuilder
query.Append(" USE [master]; ")
query.Append("IF NOT EXISTS(SELECT * FROM sys.databases Where name = '" & dbName & "') ")
query.Append(" CREATE DATABASE [" & dbName & "] ")
query.Append(" ALTER DATABASE [" & dbName & "] SET COMPATIBILITY_LEVEL = " & Versione & " ;")
query.Append(" ALTER DATABASE [" & dbName & "] SET READ_WRITE ;")
query.Append(" ALTER DATABASE [" & dbName & "] SET MULTI_USER ;")
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(query.ToString, SQLConnection)
command.ExecuteNonQuery()
_NomeDB = dbName
End Using
Return True
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
_NomeDB = ""
Return False
End Try
End Function
Friend Function CheckOrCreateTable(ByVal tableName As String, ByVal columns As List(Of Cols)) As Boolean
Try
If _NomeDB IsNot Nothing AndAlso _NomeDB.Length > 0 Then
Dim query As StringBuilder = New StringBuilder
query.Append(" USE [" & _NomeDB & "]; ")
query.Append(" IF NOT EXISTS ( SELECT * FROM sys.tables WHERE name = '" & tableName & "' ) ")
query.Append(" CREATE TABLE " & tableName & " ")
query.Append(" ( IndexRow INT IDENTITY(1,1) NOT NULL ); ")
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(query.ToString, SQLConnection)
command.ExecuteNonQuery()
End Using
query.Clear()
If columns IsNot Nothing AndAlso columns.Count > 0 Then
For i As Integer = 0 To columns.Count - 1
Dim TipoInput As String = columns(i).TInput & " "
If columns(i).Length > 0 Then
CreateColumn(tableName, columns(i).Nome, TipoInput, columns(i).Null, CStr(columns(i).Length))
Else
CreateColumn(tableName, columns(i).Nome, TipoInput, columns(i).Null)
End If
Next
End If
Return True
End If
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return False
End Function
Friend Function CreateColumn(ByVal tableName As String,
ByVal columnName As String,
ByVal TipoInput As String,
ByVal nullOrNot As String,
Optional ByVal Lunghezza As String = "-1") As Integer
Dim i As Integer = 0
Try
Dim mTipoInput As String = TipoInput
If CInt(Lunghezza) > -1 Then mTipoInput = mTipoInput & "(" & Lunghezza & ") "
Dim query As StringBuilder = New StringBuilder
query.Append(" USE [" & _NomeDB & "]; ")
query.Append(" IF NOT EXISTS (SELECT * FROM syscolumns WHERE id = OBJECT_ID('" & tableName & "') AND name = '" & columnName & "' )")
query.Append(" ALTER TABLE " & tableName)
query.Append(" ADD " & columnName & " " & mTipoInput & " " & nullOrNot)
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(query.ToString, SQLConnection)
i = command.ExecuteNonQuery()
End Using
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return i
End Function
Friend Function CheckOrCreateColumn(ByVal tableName As String,
ByVal columnName As String,
Optional ByVal inputType As String = Inputs._VARCHAR,
Optional ByVal nullOrNot As String = "NULL",
Optional ByVal Lunghezza As String = "-1") As Integer
Dim i As Integer = 0
Try
Dim mTipoInput As String = inputType
If CInt(Lunghezza) > -1 Then mTipoInput = mTipoInput & "(" & Lunghezza & ") "
Dim query As StringBuilder = New StringBuilder
query.Append(" USE [" & _NomeDB & "]; ")
query.Append(" IF NOT EXISTS (SELECT * FROM syscolumns WHERE id = OBJECT_ID('" & tableName & "') AND name = '" & columnName & "' )")
query.Append(" ALTER TABLE " & tableName)
query.Append(" ADD " & columnName & " " & mTipoInput & " " & nullOrNot)
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(query.ToString, SQLConnection)
i = command.ExecuteNonQuery()
End Using
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
#End If
End Try
Return i
End Function
Friend Function CheckOrCreateIndex(tipo As TypeIndex,
indexName As String,
tableName As String,
columnsIndexes() As String,
Optional includedColumns() As String = Nothing) As String
Dim res As String = ""
Try
' CREATE INDEX IX_TableName_Col1
' ON dbo.TableName
' (column_1)
If columnsIndexes.Length > 0 Then
Dim query As StringBuilder = New StringBuilder
query.Append(" USE [" & _NomeDB & "]; ")
query.Append(" IF NOT EXISTS (SELECT name FROM sys.indexes WHERE name = '" & indexName & "')")
Select Case tipo
Case TypeIndex.CLUSTER
query.Append(" CREATE CLUSTERED INDEX " & indexName)
Case TypeIndex.NONCOLUSTER
query.Append(" CREATE NONCLUSTERED INDEX " & indexName)
End Select
query.Append(" ON [" & tableName & "] (" & JoinParams(columnsIndexes, False).Trim & ")")
If includedColumns IsNot Nothing AndAlso includedColumns.Length > 0 Then
query.Append(" Include (" & JoinParams(includedColumns, False) & ")")
End If
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(query.ToString, SQLConnection)
command.ExecuteNonQuery()
res = indexName
End Using
End If
Catch ex As Exception
#If DEBUG Then
Debug.WriteLine(ex.ToString)
'Debugger.Break()
#End If
End Try
Return res
End Function
Friend Function InsertInto(tableName As String, listOfCols As List(Of String), listOfValues As List(Of String)) As Boolean
Try
Dim Sql As String = " USE [" & _NomeDB & "]; "
Sql &= " INSERT INTO " & tableName
If listOfCols.Count > 0 AndAlso listOfValues.Count > 0 Then
Sql &= " (" & Join(listOfCols.ToArray, ",") & ")"
Sql &= " VALUES (" & JoinParams(listOfValues.ToArray) & ")"
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(Sql, SQLConnection)
command.ExecuteNonQuery()
End Using
Return True
End If
Catch ex As Exception
#If DEBUG Then
Console.WriteLine(ex.ToString)
'Stop
#End If
End Try
Return False
End Function
Friend Function UpdateInto(tableName As String, listOfCols As List(Of String), listOfValues As List(Of String), WhereClausola As String) As Integer
Dim ret As Integer = 0
Try
Dim Sql As String = " USE [" & _NomeDB & "]; "
Sql &= " UPDATE " & tableName & " SET "
If listOfCols.Count > 0 AndAlso listOfValues.Count > 0 Then
If listOfCols.Count > 0 AndAlso listOfValues.Count > 0 Then
' UPDATE Customers
'SET
'ContactName ='Alfred Schmidt',
'City ='Hamburg'
'WHERE CustomerName ='Alfreds Futterkiste';
For i As Integer = 0 To listOfCols.Count - 1
Sql &= " " & listOfCols(i) & "=" & CStr(IIf(listOfValues(i) IsNot Nothing, listOfValues(i), "NULL")) & CStr(IIf(i < listOfCols.Count - 1, ",", ""))
Next
If WhereClausola IsNot Nothing AndAlso WhereClausola.Length > 0 Then
WhereClausola = WhereClausola.ToLower.Replace("where", " ")
Sql &= " WHERE " & WhereClausola
Using SQLConnection = New SqlConnection(_SConessione)
Open(SQLConnection)
Dim command As New SqlCommand(Sql, SQLConnection)
ret = command.ExecuteNonQuery()
End Using
End If
End If
End If
Return ret
Catch ex As Exception
#If DEBUG Then
Console.WriteLine(ex.ToString)
'Stop
#End If
End Try
Return ret
End Function
Private Function JoinParams(ByVal params() As String, Optional ByVal UseVbcrlf As Boolean = True) As String
Dim s As String = ""
Dim mVbCrlf As String = CStr(IIf(UseVbcrlf, vbCrLf, " "))
For i As Integer = 0 To params.Length - 1
If params(i) IsNot Nothing Then
If i = params.Length - 1 Then
s &= params(i) & " " & mVbCrlf
Else
s &= params(i) & ", " & mVbCrlf
End If
End If
Next
Return s
End Function
Friend Sub Open(sqlConn As SqlConnection)
Try
_SQLConnection = sqlConn
Select Case sqlConn.State
Case <> ConnectionState.Connecting
sqlConn.Close()
sqlConn.ConnectionString = _SConessione
sqlConn.Open()
End Select
Catch ex As Exception
End Try
End Sub
Friend Sub Close()
Try
If _SQLConnection IsNot Nothing Then
_SQLConnection.Close()
End If
Catch ex As Exception
Debug.WriteLine(ex.ToString)
End Try
End Sub
End Class
Module SQLUtil
Function InLIKE(s As String) As String
'%email pippo%
If s IsNot Nothing AndAlso s.Length > 0 Then
Return "%" & s & "%"
End If
Return "%%"
End Function
Function InApice(value As String) As String
If value Is Nothing Then Return "''"
If value.Length = 0 Then Return "''"
Dim appice As String = "'" '"`"
value = value.Replace("'", "''")
Return " " & appice & value & appice & " "
End Function
Function ToDate(dateStr As String) As String
If IsDate(dateStr) Then
Dim sDate As String = CDate(dateStr).ToString
Return sDate
End If
Return dateStr
End Function
Function ToDbDate(dateStr As String) As String
dateStr = New Date(dateStr)
If IsDate(dateStr) Then
Dim mDate As Date = CDate(dateStr)
Dim anno As Integer = mDate.Year
Dim mese As Integer = mDate.Month
Dim giorno As Integer = mDate.Day
Dim ora As Integer = mDate.Hour
Dim minuto As Integer = mDate.Minute
If Not IsNumeric(anno) Then anno = 0
If Not IsNumeric(mese) Then mese = 0
If Not IsNumeric(giorno) Then giorno = 0
If Not IsNumeric(ora) Then ora = 0
If Not IsNumeric(minuto) Then minuto = 0
anno = Strings.Format(anno, "0000")
mese = Strings.Format(mese, "00")
giorno = Strings.Format(giorno, "00")
ora = Strings.Format(ora, "00")
minuto = Strings.Format(minuto, "00")
Dim sDate As String = CStr(anno) & CStr(mese) & CStr(giorno) & CStr(ora) & CStr(minuto)
Return sDate
End If
Return ""
End Function
Function FromDbDate(s As String, Optional ancheOraEMinuti As Boolean = False) As String
If s Is Nothing Then Return ""
If s.Length = 0 Then Return ""
If s.Length > 12 Then
Dim data As String = ""
Dim anno As String = s.Substring(0, 4)
Dim mese As String = s.Substring(5, 2)
Dim giorno As String = s.Substring(7, 2)
Dim ora As String = s.Substring(9, 2)
Dim minuti As String = s.Substring(11, 2)
End If
Return ""
End Function
End Module