Add ability to determine if a database view exists. Closes #5.

Add support for SQL Server, MySQL and HyperSQL via the SQLViewExists class.

DatabaseObjects.vbproj

@@ -327,6 +327,7 @@
     <Compile Include="Contraints\IConstraint.vb" />
     <Compile Include="SQL\Views\SQLCreateView.vb" />
     <Compile Include="SQL\Views\SQLDropView.vb" />
+    <Compile Include="SQL\Views\SQLViewExists.vb" />
   </ItemGroup>
   <ItemGroup>
     <BootstrapperPackage Include="Microsoft.Net.Client.3.5">

SQL/Views/SQLViewExists.vb

@@ -0,0 +1,79 @@
+' ___________________________________________________
+'
+'  © Hi-Integrity Systems 2012. All rights reserved.
+'  www.hisystems.com.au - Toby Wicks
+' ___________________________________________________
+'
+
+Option Strict On
+Option Explicit On 
+
+Namespace SQL
+
+    ''' --------------------------------------------------------------------------------
+    ''' <summary>
+    ''' This class can be used to determine whether a view exists. This class can be 
+    ''' used will all databases. If after running the SQL statement the data set is not
+    ''' empty then the view exists. 
+    ''' </summary>
+    ''' --------------------------------------------------------------------------------
+    Public Class SQLViewExists
+        Inherits SQLStatement
+
+        Private pstrViewName As String
+
+        Public Sub New(ByVal strViewName As String)
+
+            If String.IsNullOrEmpty(strViewName) Then
+                Throw New ArgumentNullException
+            End If
+
+            pstrViewName = strViewName
+
+        End Sub
+
+        Public Overrides ReadOnly Property SQL() As String
+            Get
+
+                Dim strSQL As String = String.Empty
+                Dim objSelect As SQLSelect
+
+                Select Case Me.ConnectionType
+                    Case Database.ConnectionType.MicrosoftAccess
+                        Throw New NotSupportedException
+                    Case Database.ConnectionType.MySQL
+                        strSQL = "SHOW VIEWS LIKE " & SQLConvertValue(pstrViewName, Me.ConnectionType)
+                    Case Database.ConnectionType.SQLServer
+                        objSelect = New SQLSelect
+                        With objSelect
+                            .ConnectionType = Me.ConnectionType
+                            .Tables.Add("sysobjects")
+                            .Where.Add("Name", ComparisonOperator.EqualTo, pstrViewName)
+                            .Where.Add("XType", ComparisonOperator.EqualTo, "V")       'V = User defined view
+                            strSQL = .SQL
+                        End With
+                    Case Database.ConnectionType.Pervasive
+                        Throw New NotSupportedException
+                    Case Database.ConnectionType.HyperSQL
+                        objSelect = New SQLSelect
+                        With objSelect
+                            .ConnectionType = Me.ConnectionType
+                            .Tables.Add("VIEWS").SchemaName = "INFORMATION_SCHEMA"
+                            .Where.Add("TABLE_SCHEMA", ComparisonOperator.EqualTo, "PUBLIC")
+                            .Where.Add("TABLE_NAME", ComparisonOperator.EqualTo, pstrViewName)
+                            strSQL = .SQL
+                        End With
+                    Case Database.ConnectionType.SQLServerCompactEdition
+                        Throw New NotSupportedException
+                    Case Else
+                        Throw New NotImplementedException(Me.ConnectionType.ToString)
+                End Select
+
+                Return strSQL
+
+            End Get
+        End Property
+
+    End Class
+
+End Namespace