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‘ MySqlHelper VB.NET class
‘ http://www.maxvergelli.com/

‘ Copyright (c) 2016 Max Vergelli

‘ Vers. 2.1.0
‘ Date: 21/03/2016

‘ Description:
‘ .NET helper class to easly execute SQL commands against a MySQL database,
‘ execute stored procedures, get or programmatically update DataSet objects,
‘ and convert to and from MySQL datetime types.
‘
‘ Before use this class, You have to install and import in your project the
‘ last MySQL Connector/NET at
‘ http://dev.mysql.com/doc/refman/5.0/es/connector-net.html

‘ Permission is hereby granted, free of charge, to any person obtaining a copy
‘ of this software and associated documentation files (the "Software"), to deal
‘ in the Software without restriction, including without limitation the rights
‘ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
‘ copies of the Software, and to permit persons to whom the Software is
‘ furnished to do so, subject to the following conditions:

‘ The above copyright notice and this permission notice shall be included in
‘ all copies or substantial portions of the Software.

‘ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
‘ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
‘ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
‘ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
‘ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
‘ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
‘ THE SOFTWARE.

Imports System.Data
Imports System.Globalization
Imports MySql.Data.MySqlClient

Public Class MySqlHelper

Private _cnx_string As String = Nothing
Private _cnx_obj As MySqlConnection = Nothing

Private Function IsConnectionAlive() As Boolean
Dim is_alive As Boolean = False
If _cnx_obj IsNot Nothing AndAlso _cnx_obj.State <> ConnectionState.Closed Then
is_alive = True
End If
Return is_alive
End Function

Private Sub CloseConnection()

Try

If IsConnectionAlive() Then
_cnx_obj.Close()
End If
_cnx_obj = Nothing

Catch ex As Exception

_cnx_obj = Nothing

End Try

End Sub

Public ReadOnly Property ConnectionString() As String
Get
Return _cnx_string
End Get
End Property

Public Function IsOpen() As Boolean
Return IsConnectionAlive()
End Function

Public Sub New(Optional ByVal db_connection_string As String = "", _
Optional ByVal open_connection As Boolean = False)

_cnx_string = db_connection_string

If _cnx_string.Length > 0 And open_connection = True Then

Dim is_open As Boolean = Open(_cnx_string)

End If

End Sub

Public Function Open(ByVal db_connection_string As String) As Boolean

Dim success As Boolean = False
Try

If IsConnectionAlive() = False Then

If db_connection_string.Length > 0 AndAlso _cnx_obj Is Nothing Then

_cnx_string = db_connection_string
_cnx_obj = New MySqlConnection
_cnx_obj.ConnectionString = _cnx_string
_cnx_obj.Open()
success = True

End If

End If

Catch ex As Exception

CloseConnection()
success = False

End Try
Return success

End Function

Public Sub Close()

CloseConnection()

End Sub

Protected Overrides Sub Finalize()
CloseConnection()
End Sub

‘get a DataRow object with the first row of a SQL select command
Public Function SelectFirstRow(ByVal sql_select As String) As DataRow

Dim ds As DataSet = SelectRows(sql_select)
If ds Is Nothing Then
Return Nothing
End If
If ds.Tables.Count < 1 Then
Return Nothing
End If
If ds.Tables(0).Rows.Count < 1 Then
Return Nothing
End If
Return ds.Tables(0).Rows(0)

End Function

‘get a DataSet object with the rows of a SQL select command
Public Function SelectRows(ByVal sql_select As String) As DataSet

Dim ds As DataSet = Nothing
Try

If IsConnectionAlive() Then

Dim cmd As MySqlCommand = New MySqlCommand(sql_select, _cnx_obj)

Dim da As MySqlDataAdapter = New MySqlDataAdapter
da.SelectCommand = cmd

ds = New DataSet
da.Fill(ds)

da = Nothing

End If

Catch ex As Exception

ds = Nothing

End Try
Return ds

End Function

‘Execute a MySql Stored Procedure
Public Overloads Function ExecuteStoredProcedure(ByVal stored_procedure_name As String) As DataSet

Return ExecuteProcedure(stored_procedure_name)

End Function

‘Execute a MySql Stored Procedure with parameters

‘How to create the parameters
‘Dim param As MySqlParameter = New MySqlParameter("?v_id", MySqlDbType.Int32)
‘param.Value = 1
‘param.Direction = ParameterDirection.Input

Public Overloads Function ExecuteStoredProcedure(ByVal stored_procedure_name As String, _
ByVal ParamArray parameters As MySqlParameter()) As DataSet

Return ExecuteProcedure(stored_procedure_name, parameters)

End Function

Private Function ExecuteProcedure(ByVal procedure_name As String, _
ByVal ParamArray sql_parameters As MySqlParameter()) As DataSet

Dim ds As DataSet = Nothing
Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(procedure_name, _cnx_obj)

cmd.CommandType = CommandType.StoredProcedure

If sql_parameters IsNot Nothing Then
For Each p As MySqlParameter In sql_parameters
cmd.Parameters.Add(p)
Next
End If

Dim da As MySqlDataAdapter = New MySqlDataAdapter
da.SelectCommand = cmd
ds = New DataSet
da.Fill(ds)
da = Nothing

cmd.Parameters.Clear()

End If
Catch ex As Exception

ds = Nothing

End Try

Return ds

End Function

‘UpdateRows() function automatically generates single-table commands used to reconcile changes made to a DataSet
‘with the associated table in the MySQL database.
‘The function gets
‘ – the SQL SELECT used to populate the dataset
‘ – the updated dataset
‘ – the table name that must be updated in the database
‘Note:
‘The SQL SELECT must also return at least one primary key or unique column, otherwise an exception is generated;

Public Function UpdateRows(ByVal sql_select As String, ByRef input_dataset As DataSet, ByVal table_name As String) As Boolean

Dim success As Boolean = False
Try

If IsConnectionAlive() Then

Dim data_adapter As New MySqlDataAdapter(sql_select, _cnx_obj)
Dim cmd_builder As New MySqlCommandBuilder(data_adapter)
data_adapter.Update(input_dataset, table_name)
success = True

End If

Catch ex As Exception

success = False

End Try

Return success

End Function

‘To use a MySqlDataReader,
‘You have to use OpenReader() and CloseReader() functions like in the following example:
‘
‘ Public Sub ReadMyData(ByVal connection_string As String)
‘
‘ Dim mysql As MySqlHelper = New MySqlHelper()
‘ mysql.Open(connection_string)
‘
‘ Dim sql As String = "SELECT OrderID, CustomerID FROM Orders"
‘ Dim reader As MySqlDataReader = Nothing
‘
‘ mysql.OpenReader(reader, sql)
‘ While reader.Read()
‘ Console.WriteLine((reader.GetInt32(0) & ", " & reader.GetString(1)))
‘ End While
‘ mysql.CloseReader(reader)
‘
‘ mysql.Close()
‘
‘ End Sub

Public Sub OpenReader(ByRef reader As MySqlDataReader, ByVal sql_select As String)

Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(sql_select, _cnx_obj)
reader = cmd.ExecuteReader()

End If

Catch ex As Exception

reader = Nothing

End Try

End Sub

Public Sub CloseReader(ByRef reader As MySqlDataReader)

Try

reader.Close()

Catch ex As Exception

End Try

End Sub

‘Execute SQL command and return the number of records affected
Public Function Execute(ByVal sql_command As String) As Long

Dim affected_rows As Long = 0

Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(sql_command, _cnx_obj)

affected_rows = cmd.ExecuteNonQuery()

End If

Catch ex As Exception

affected_rows = 0

End Try

Return affected_rows

End Function

‘GetSingleValue() function executes the query, and returns the value of the first column of the first row in the
‘result set returned by the query. Extra columns or rows are ignored.
‘Note:
‘Use the GetSingleValue() method to retrieve a single value (for example, an aggregate value)
‘from a database, like "select count(*) from region"

Public Overloads Function GetSingleValue(ByVal sql_select As String) As Object

Return ExecuteScalar(sql_select, DirectCast(Nothing, MySqlParameter()))

End Function

Public Overloads Function GetSingleValue(ByVal sql_select As String, ByVal ParamArray sql_parameters As MySqlParameter()) As Object

Return ExecuteScalar(sql_select, sql_parameters)

End Function

‘ExecuteScalar: Executes the query, and returns the value (integer/string) of the first column of the first row in the result set returned by the query. Extra columns or rows are ignored.
Private Function ExecuteScalar(ByVal sql_select As String, ByVal ParamArray sql_parameters As MySqlParameter()) As Object

Dim row As Object = Nothing
Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(sql_select, _cnx_obj)
If sql_parameters IsNot Nothing Then
For Each p As MySqlParameter In sql_parameters
cmd.Parameters.Add(p)
Next
End If
row = cmd.ExecuteScalar()
cmd.Parameters.Clear()

End If
Catch ex As Exception

row = Nothing

End Try

Return row

End Function

’25/1/12 -> 2012-01-25
Public Overloads Function ConvertToMySqlDate(ByVal input_date As Date) As String

Return input_date.ToString("yyyy-MM-dd")

End Function

’25/1/12 -> 2012-01-25
Public Overloads Function ConvertToMySqlDate(ByVal input_date As String) As String

Return ConvertDateTime(input_date, DATETIME_TYPE.MYSQL, True)

End Function

’25/1/12 13:00 -> 2012-01-25 13:00:00
Public Overloads Function ConvertToMySqlDateTime(ByVal input_datetime As DateTime) As String

Return input_datetime.ToString("yyyy-MM-dd HH:mm:ss")

End Function

’25/1/12 13:00 -> 2012-01-25 13:00:00
Public Overloads Function ConvertToMySqlDateTime(ByVal input_datetime As String) As String

Return ConvertDateTime(input_datetime, DATETIME_TYPE.MYSQL)

End Function

‘2012-01-25 -> 25-01-2012
Public Overloads Function ConvertToDate(ByVal mysql_date As Date) As String

Return mysql_date.ToString("dd-MM-yyyy")

End Function

‘2012-01-25 -> 25-01-2012
Public Overloads Function ConvertToDate(ByVal mysql_date As String) As String

Return ConvertDateTime(mysql_date, DATETIME_TYPE.SYSTEM, True)

End Function

‘2012-01-25 13:00:00 -> 25-01-2012 13:00:00
Public Overloads Function ConvertToDateTime(ByVal mysql_datetime As DateTime) As String

Return mysql_datetime.ToString("dd-MM-yyyy HH:mm:ss")

End Function

‘2012-01-25 13:00:00 -> 25-01-2012 13:00:00
Public Overloads Function ConvertToDateTime(ByVal mysql_datetime As String) As String

Return ConvertDateTime(mysql_datetime, DATETIME_TYPE.SYSTEM)

End Function

Private Enum DATETIME_TYPE As Integer
SYSTEM = 0
MYSQL = 1
End Enum

Private Function ConvertDateTime(ByVal input_datetime As String, ByVal output_datetime_type As DATETIME_TYPE, _
Optional ByVal get_only_date As Boolean = False) As String

‘The function returns a datetime in a well-formatted string for regular or MySQL use.
‘You have to insert a datetime string formatted by {,/,-,.,:} symbols.
‘Besides, for the input date, You need to specify "day, month and year";
‘for the time, only "hour and minutes", "seconds" doesn’t matter.

‘The function returns Nothing if an error is encountered.

‘You can select one of the following datetime types as output:
‘SYSTEM: "(2 digits day)-(2 digits month)-(4 digits year) hours:minutes:seconds"
‘MYSQL: "(4 digits year)-(2 digits month)-(2 digits day) hours:minutes:seconds"

‘examples:
‘for a regular datetime in input and
‘a MySql datetime as output, You ‘ll get…

’25-1-08 -> 2008-01-25 00:00:00
’25/1/08 -> 2008-01-25 00:00:00
’25/1/08 12:00 -> 2008-01-25 12:00:00
’25-1-08 12:00 -> 2008-01-25 12:00:00
‘25.1.08 12:00 -> 2008-01-25 12:00:00
‘25.1.08 12.00 -> 2008-01-25 12:00:00
‘25.1.08 12.00.23 -> 2008-01-25 12:00:23

Dim dt_out As String = Nothing
Dim dt_type As String = ""
If output_datetime_type = DATETIME_TYPE.MYSQL Then
dt_type = "yyyy-MM-dd HH’:’mm’:’ss"
Else
dt_type = "dd-MM-yyyy HH’:’mm’:’ss"
End If
Try
If input_datetime.IndexOf(".", 0, CompareMethod.Binary) > 0 Then
Dim tmp() As String = input_datetime.Split(" ")
If tmp.GetUpperBound(0) > 0 Then
input_datetime = tmp(0).Replace(".", "-") & " " & tmp(1).Replace(".", ":")
End If
End If
Dim myDTFI As DateTimeFormatInfo = New CultureInfo("it-IT", False).DateTimeFormat
myDTFI.FullDateTimePattern = "dd-MM-yyyy HH’:’mm’:’ss"
myDTFI.DateSeparator = "-"
myDTFI.TimeSeparator = ":"
Dim myDT As New DateTime
myDT = System.Convert.ToDateTime(input_datetime, myDTFI)
dt_out = Format(myDT, dt_type)
myDT = Nothing
myDTFI = Nothing
If get_only_date = True Then
Dim s() As String = dt_out.Split(" ")
If s.GetUpperBound(0) > 0 Then
dt_out = s(0)
End If
End If
Catch ex As Exception
dt_out = Nothing
End Try
Return dt_out

End Function

End Class