#Offline Driver
##creating the driver
In order to implement a driver that operates completely independent of a database, it is necessary to override the following methods at a minimum:
- GetAllTables
- GetColumns
- GetDataSet
- DetectVersion
- CheckConnection
- GetAllStoredProcedures
This will allow Izenda to perform the operations it needs to in order to get database schema information and produce datasets in a completely custom manner. Below is an example of how one might override these to create a driver that does not connect to a database.
##C♯ Example
using System;
using System.Collections.Generic;
using Izenda.AdHoc;
using Izenda.AdHoc.Database;
using System.Data;
[Serializable]
public class OfflineDriver : MSSQLDriver
{
Dictionary<string, Type> colTypes = new Dictionary<string, Type>()
{ {"[dbo].[Fruits].[Price]", typeof(double)},
{"[dbo].[Drinks].[Price]", typeof(double)},
{"[dbo].[Fruits].[Name]", typeof(string)},
{"[dbo].[Drinks].[Name]", typeof(string)},
{"[dbo].[Fruits].[Color]", typeof(string)},
{"[dbo].[Drinks].[Alcohol]", typeof(string)}};
Dictionary<string, object[]> colData = new Dictionary<string, object[]>()
{ {"[dbo].[Fruits].[Price]", new object[] {1.24, 2.61, 1.38, 3.21}},
{"[dbo].[Drinks].[Price]", new object[] {9.56, 7.11, 9.41, 7.42}},
{"[dbo].[Fruits].[Name]", new object[] {"Apple", "Pear", "Plum", "Apricot"}},
{"[dbo].[Drinks].[Name]", new object[] {"Beer", "Tea", "Whiskey", "Coffee"}},
{"[dbo].[Fruits].[Color]", new object[] {"Green", "Yellow", "Black", "Orange"}},
{"[dbo].[Drinks].[Alcohol]", new string[] {"Yes", "No", "Yes", "No"}}};
public override Table[] GetAllTables()
{
List<Table> tables = new List<Table>();
tables.Add(new Table("Fruits", "dbo", TableType.Table));
tables.Add(new Table("Drinks", "dbo", TableType.Table));
return tables.ToArray();
}
public override Column[] GetColumns(Table table)
{
List<Column> columns = new List<Column>();
columns.Add(new Column("Price", SqlType.Money));
columns.Add(new Column("Name", SqlType.VarChar));
if (table.Name == "Fruits")
columns.Add(new Column("Color", SqlType.VarChar));
if (table.Name == "Drinks")
columns.Add(new Column("Alcohol", SqlType.VarChar));
return columns.ToArray();
}
protected override DataSet GetDataSet(IDbCommand command, Report report, string reportPart, string uniqueID)
{
if (report == null || String.IsNullOrEmpty(reportPart))
return base.GetDataSet(command, report, reportPart, uniqueID);
DataSet ds = new DataSet();
DataTable dt = new DataTable();
ds.Tables.Add(dt);
foreach (Field f in report.Fields)
dt.Columns.Add(new DataColumn(f.Description, colTypes[f.DbColumn.FullName]));
int top = report.Top;
if (top <= 0 || top > 4)
top = 4;
for (int i = 0; i < top; i++)
{
DataRow dr = dt.NewRow();
for (int cc = 0; cc < report.Fields.Count; cc++)
dr[cc] = colData[report.Fields[cc].DbColumn.FullName][i];
dt.Rows.Add(dr);
}
return ds;
}
public override Version DetectVersion()
{
return new Version(1, 0);
}
public override void CheckConnection()
{
}
public override StoredProcedure[] GetAllStoredProcedures()
{
return new StoredProcedure[0];
}
public OfflineDriver()
{
}
}##VB.NET Example
Imports System
Imports System.Collections.Generic
Imports Izenda.AdHoc
Imports Izenda.AdHoc.Database
Imports System.Data
<Serializable>
Public Class OfflineDriver
Inherits MSSQLDriver
Dim colTypes As Dictionary(Of String, Type) = New Dictionary(Of String, Type)() From
{{"[dbo].[Fruits].[Price]", GetType(Double)},
{"[dbo].[Drinks].[Price]", GetType(Double)},
{"[dbo].[Fruits].[Name]", GetType(String)},
{"[dbo].[Drinks].[Name]", GetType(String)},
{"[dbo].[Fruits].[Color]", GetType(String)},
{"[dbo].[Drinks].[Alcohol]", GetType(String)}}
Dim colData As Dictionary(Of String, Object()) = New Dictionary(Of String, Object())() From
{{"[dbo].[Fruits].[Price]", New Object() {1.24, 2.61, 1.38, 3.21}},
{"[dbo].[Drinks].[Price]", New Object() {9.56, 7.11, 9.41, 7.42}},
{"[dbo].[Fruits].[Name]", New Object() {"Apple", "Pear", "Plum", "Apricot"}},
{"[dbo].[Drinks].[Name]", New Object() {"Beer", "Tea", "Whiskey", "Coffee"}},
{"[dbo].[Fruits].[Color]", New Object() {"Green", "Yellow", "Black", "Orange"}},
{"[dbo].[Drinks].[Alcohol]", New String() {"Yes", "No", "Yes", "No"}}}
Public Overrides Function GetAllTables() As Table()
Dim tables = New List(Of Table)
tables.Add(New Table("Fruits", "dbo", TableType.Table))
tables.Add(New Table("Drinks", "dbo", TableType.Table))
Return tables.ToArray()
End function
Public Overrides Function GetColumns(table As Table) As Column()
Dim columns = New List(Of Column)
columns.Add(New Column("Price", SqlType.Money))
columns.Add(New Column("Name", SqlType.VarChar))
If table.Name.Equals("Fruits") Then
columns.Add(New Column("Color", SqlType.VarChar))
End If
If table.Name.Equals("Drinks") Then
columns.Add(New Column("Alcohol", SqlType.VarChar))
End If
Return columns.ToArray()
End function
Protected Overrides Function GetDataSet(command As IDbCommand, report As Report, reportPart As String, uniqueID As String) As DataSet
If report Is Nothing OrElse String.IsNullOrEmpty(reportPart) Then
Return MyBase.GetDataSet(command, report, reportPart, uniqueID)
End If
Dim ds As New DataSet()
Dim dt As New DataTable()
ds.Tables.Add(dt)
For Each f As Field In report.Fields
dt.Columns.Add(New DataColumn(f.Description, colTypes(f.DbColumn.FullName)))
Next
Dim top = report.Top
If top <= 0 OrElse top > 4 Then
top = 4
End If
For i As Integer = 0 To top - 1 Step 1
Dim dr = dt.NewRow()
For cc As Integer = 0 To report.Fields.Count - 1
dr(cc) = colData(report.Fields(cc).DbColumn.FullName)(i)
Next
dt.Rows.Add(dr)
Next
Return ds
End Function
Public Overrides Function DetectVersion() As Version
Return New Version(1, 0)
End Function
Public Overrides Sub CheckConnection()
End Sub
Public Overrides Function GetAllStoredProcedures() As StoredProcedure()
Return New StoredProcedure() {}
End Function
Public Sub New()
End Sub
End Class