Changes in c62137e: Updated many to many database join (markdown)

				FAQ/many-to-many-database-join.md
			
          @@ -12,7 +12,26 @@ In order to achieve the results required for this scenario, some understanding a

           For this tutorial, all changes being made will exist in your CustomAdHocConfig class that is normally contained inside the Global.asax.

          -First, we need to modify the [[InitializeReporting()|/FAQ/InitializeReporting]] method:

          +First, we need an instance variable to hold a reference to the driver.

          +

          +``` csharp

          +Public Class CustomAdHocConfig : FileSystemAdHocConfig

          +  private oldDriver As Driver = null;

          +

          +  {...} 'InitializeReporting, PreExecuteReportSet, etc.

          +End Class

          +```

          +

          +``` visualbasic

          +public class CustomAdHocConfig Inherits FileSystemAdHocConfig

          +{

          +  private oldDriver As Drier = Nothing

          +

          +  {...} //InitializeReporting, PreExecuteReportSet, etc.

          +}

          +```

          +

          +Next, we need to modify the [[InitializeReporting()|/FAQ/InitializeReporting]] method:

           ``` csharp

           public static void InitializeReporting() {

          @@ -24,6 +43,7 @@ public static void InitializeReporting() {

             AdHocSettings.SqlServerConnectionString = @"INSERT_YOUR_CONNECTION_STRING_HERE";

             {...}

             AdHocContext.Driver.AddConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]");

          +  AdHocSettings.visibleDataSources = new string[] { "[dbo].[Orders]", "[dbo].[Suppliers]" }; //Set our visible data sources to exclude our middle table

             HttpContext.Current.Session["ReportingInitialized"] = true;

           }

           ```

          @@ -42,7 +62,7 @@ Public Shared Sub InitializeReporting()

             HttpContext.Current.Session("ReportingInitialized") = True

           End Sub

           ```

          -The statement critical to the [[InitializeReporting()|/FAQ/InitializeReporting]] method is the AddConstraint method call. Here, we set up a relationship between two columns in our two tables with a many-to-many relationship. At this point, the connector table has not entered the equation. This constraint must exist in order to select the two tables with a many-to-many relationship on the datasources tab.

          +The statement critical to the [[InitializeReporting()|/FAQ/InitializeReporting]] method is the AddConstraint method call. Here, we set up a relationship between two columns in our two tables with a many-to-many relationship. At this point, the connector table has not entered the equation. This constraint must exist in order to select the two tables with a many-to-many relationship on the datasources tab. We will also reset the driver to re-obtain the database schema objects. This is because setting VisibleDataSources after the initialization of the current driver will not load the columns for any additional data sources.

           _*NOTE:* The two columns in the fake constraint MUST have the same datatype._

          @@ -51,7 +71,11 @@ Next, we modify the [[PreExecuteReportSet()|/FAQ/PreExecuteReportSet]] method.

           ``` csharp

           public override void PreExecuteReportSet(ReportSet reportSet) {

             base.PreExecuteReportSet(reportSet);

          -  AdHocContext.Driver.RemoveConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]"); //temporarily remove the constraint

          +  oldDriver = AdHocContext.Driver;

          +  AdHocContext.Driver = new MSSQLDriver(AdHocSettings.SqlServerConnectionString); //Set the specific type of driver we were using before

          +  AdHocSettings.VisibleDataSources = new string[] { "[dbo].[Orders]", [dbo].[Suppliers]", "[dbo].[testcon]" }; //testcon is the name of the middle table we want to join with

          +  AdHocContext.Driver.AddConstraint("[dbo].[Orders].[OrderID]", "[dbo].[testcon].[ordernum]");

          +  AdHocContext.Driver.AddConstraint("[dbo].[Suppliers].[SupplierID]", "[dbo].[testcon].[supplier]"); //Add the correct constraints to the driver

             if(reportSet.JoinedTables.Count > 0) //check if we have selected multiple tables

             {

               IEnumerable<JoinedTable> jts = (from JoinedTable jt in reportSet.JoinedTables

          @@ -59,7 +83,7 @@ public override void PreExecuteReportSet(ReportSet reportSet) {

                        (jt.RightConditionTable.Contains("Orders") || jt.RightConditionTable.Contains("Suppliers"))

                      select jt); //use LINQ to check if we selected the tables we want to define the relationship for

               JoinedTable middleJT = new JoinedTable(){

          -            TableName = "[dbo].[testcon]" //This is our connector table                   

          +            TableName = "[dbo].[testcon]"                 

               };

               if(jts.Count() == 2) //We have both tables that we want

               {

          @@ -67,7 +91,7 @@ public override void PreExecuteReportSet(ReportSet reportSet) {

                 reportSet.JoinedTables.Remove(jts.ToArray()[1]); 

                 reportSet.JoinedTables.Remove(jts.ToArray()[0]);

                 //if any other joined tables exist, you can modify them according to your needs. This tutorial will not cover that scenario.

          -      reportSet.JoinedTables.Add(middleJT); //Add the connector table

          +      reportSet.JoinedTables.Add(middleJT); //Add the connector table first. In this example, it will be the table in the FROM. Orders and Suppliers will be the JOINed tables.

                 reportSet.JoinedTables.Add(new JoinedTable()

                 {

                   TableName = "[dbo].[Orders]",

          @@ -93,7 +117,11 @@ public override void PreExecuteReportSet(ReportSet reportSet) {

           ``` visualbasic

           Public Overrides Sub PreExecuteReportSet(ByVal reportSet As ReportSet)

             MyBase.PreExecuteReportSet(reportSet)

          -  AdHocContext.Driver.RemoveConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]")

          +  oldDriver = AdHocContext.Driver

          +  AdHocContext.Driver = new MSSQLDriver(AdHocSettings.SqlServerConnectionString) 'Set the specific type of driver we were using before

          +  AdHocSettings.VisibleDataSources = New string() { "[dbo].[Orders]", [dbo].[Suppliers]", "[dbo].[testcon]" } 'testcon is the name of the middle table we want to join with

          +  AdHocContext.Driver.AddConstraint("[dbo].[Orders].[OrderID]", "[dbo].[testcon].[ordernum]")

          +  AdHocContext.Driver.AddConstraint("[dbo].[Suppliers].[SupplierID]", "[dbo].[testcon].[supplier]") 'Add the correct constraints to the driver

             If (reportSet.JoinedTables.Count > 0) Then

               Dim jts As IEnumerable(Of JoinedTable) = (From jt As JoinedTable In reportSet.JoinedTables

                 Where (jt.DbTable.Name.Contains("Orders") OrElse jt.DbTable.Name.Contains("Suppliers")) OrElse

          @@ -128,22 +156,22 @@ End Sub

           The above code in the [[PreExecuteReportSet()|/FAQ/PreExecuteReportSet]] method will re-define the relationship between the two tables in a many-to-many relationship and insert the connector table silently. This will produce a working join on the two tables while leaving out the pre-defined fake join. The user will be able to freely select the two tables in the many-to-many relationship without seeing the connecting table.

          -Finally, we need a statement in the [[PostExecuteReportSet()|/FAQ/PostExecuteReportSet]] method.

          +Finally, we need a statement in the [[PostExecuteReportSet()|/FAQ/PostExecuteReportSet]] method to reset the driver.

           ``` csharp

           public override void PostExecuteReportSet(ReportSet reportSet)

           {

             base.PostExecuteReportSet(reportSet);

          -  AdHocContext.Driver.AddConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]");

          +  AdHocContext.Driver = oldDriver;

           }

           ```

           ``` visualbasic

           Public Overrides Sub PostExecuteReportSet(ByVal reportSet As ReportSet)

             MyBase.PostExecuteReportSet(reportSet)

          -  AdHocContext.Driver.AddConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]")

          +  AdHocContext.Driver = oldDriver

           End Sub

           ```

          -Re-adding the constraint after report execution will ensure that the tables will be selectable again when the user makes subsequent trips to the Report Designer. Other users in the system without the ability to select the datasources in question will not see any change in their current behavior. Report definitions using the relationship will not reflect the internal process. The fake constraint will appear in the definition.

          \ No newline at end of file

          +Resetting the driver after report execution will ensure that the tables with no relationship will be selectable again when the user makes subsequent trips to the Report Designer. Other users in the system without the ability to select the datasources in question will not see any change in their current behavior. Report definitions using the relationship will not reflect the internal process. The fake constraint will appear in the definition.

          \ No newline at end of file

...	...	@@ -12,7 +12,26 @@ In order to achieve the results required for this scenario, some understanding a
12	12
13	13	For this tutorial, all changes being made will exist in your CustomAdHocConfig class that is normally contained inside the Global.asax.
14	14
15		-First, we need to modify the [[InitializeReporting()\|/FAQ/InitializeReporting]] method:
	15	+First, we need an instance variable to hold a reference to the driver.
	16	+
	17	+``` csharp
	18	+Public Class CustomAdHocConfig : FileSystemAdHocConfig
	19	+ private oldDriver As Driver = null;
	20	+
	21	+ {...} 'InitializeReporting, PreExecuteReportSet, etc.
	22	+End Class
	23	+```
	24	+
	25	+``` visualbasic
	26	+public class CustomAdHocConfig Inherits FileSystemAdHocConfig
	27	+{
	28	+ private oldDriver As Drier = Nothing
	29	+
	30	+ {...} //InitializeReporting, PreExecuteReportSet, etc.
	31	+}
	32	+```
	33	+
	34	+Next, we need to modify the [[InitializeReporting()\|/FAQ/InitializeReporting]] method:
16	35
17	36	``` csharp
18	37	public static void InitializeReporting() {
...	...	@@ -24,6 +43,7 @@ public static void InitializeReporting() {
24	43	AdHocSettings.SqlServerConnectionString = @"INSERT_YOUR_CONNECTION_STRING_HERE";
25	44	{...}
26	45	AdHocContext.Driver.AddConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]");
	46	+ AdHocSettings.visibleDataSources = new string[] { "[dbo].[Orders]", "[dbo].[Suppliers]" }; //Set our visible data sources to exclude our middle table
27	47	HttpContext.Current.Session["ReportingInitialized"] = true;
28	48	}
29	49	```
...	...	@@ -42,7 +62,7 @@ Public Shared Sub InitializeReporting()
42	62	HttpContext.Current.Session("ReportingInitialized") = True
43	63	End Sub
44	64	```
45		-The statement critical to the [[InitializeReporting()\|/FAQ/InitializeReporting]] method is the AddConstraint method call. Here, we set up a relationship between two columns in our two tables with a many-to-many relationship. At this point, the connector table has not entered the equation. This constraint must exist in order to select the two tables with a many-to-many relationship on the datasources tab.
	65	+The statement critical to the [[InitializeReporting()\|/FAQ/InitializeReporting]] method is the AddConstraint method call. Here, we set up a relationship between two columns in our two tables with a many-to-many relationship. At this point, the connector table has not entered the equation. This constraint must exist in order to select the two tables with a many-to-many relationship on the datasources tab. We will also reset the driver to re-obtain the database schema objects. This is because setting VisibleDataSources after the initialization of the current driver will not load the columns for any additional data sources.
46	66
47	67	_NOTE: The two columns in the fake constraint MUST have the same datatype._
48	68
...	...	@@ -51,7 +71,11 @@ Next, we modify the [[PreExecuteReportSet()\|/FAQ/PreExecuteReportSet]] method.
51	71	``` csharp
52	72	public override void PreExecuteReportSet(ReportSet reportSet) {
53	73	base.PreExecuteReportSet(reportSet);
54		- AdHocContext.Driver.RemoveConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]"); //temporarily remove the constraint
	74	+ oldDriver = AdHocContext.Driver;
	75	+ AdHocContext.Driver = new MSSQLDriver(AdHocSettings.SqlServerConnectionString); //Set the specific type of driver we were using before
	76	+ AdHocSettings.VisibleDataSources = new string[] { "[dbo].[Orders]", [dbo].[Suppliers]", "[dbo].[testcon]" }; //testcon is the name of the middle table we want to join with
	77	+ AdHocContext.Driver.AddConstraint("[dbo].[Orders].[OrderID]", "[dbo].[testcon].[ordernum]");
	78	+ AdHocContext.Driver.AddConstraint("[dbo].[Suppliers].[SupplierID]", "[dbo].[testcon].[supplier]"); //Add the correct constraints to the driver
55	79	if(reportSet.JoinedTables.Count > 0) //check if we have selected multiple tables
56	80	{
57	81	IEnumerable<JoinedTable> jts = (from JoinedTable jt in reportSet.JoinedTables
...	...	@@ -59,7 +83,7 @@ public override void PreExecuteReportSet(ReportSet reportSet) {
59	83	(jt.RightConditionTable.Contains("Orders") \|\| jt.RightConditionTable.Contains("Suppliers"))
60	84	select jt); //use LINQ to check if we selected the tables we want to define the relationship for
61	85	JoinedTable middleJT = new JoinedTable(){
62		- TableName = "[dbo].[testcon]" //This is our connector table
	86	+ TableName = "[dbo].[testcon]"
63	87	};
64	88	if(jts.Count() == 2) //We have both tables that we want
65	89	{
...	...	@@ -67,7 +91,7 @@ public override void PreExecuteReportSet(ReportSet reportSet) {
67	91	reportSet.JoinedTables.Remove(jts.ToArray()[1]);
68	92	reportSet.JoinedTables.Remove(jts.ToArray()[0]);
69	93	//if any other joined tables exist, you can modify them according to your needs. This tutorial will not cover that scenario.
70		- reportSet.JoinedTables.Add(middleJT); //Add the connector table
	94	+ reportSet.JoinedTables.Add(middleJT); //Add the connector table first. In this example, it will be the table in the FROM. Orders and Suppliers will be the JOINed tables.
71	95	reportSet.JoinedTables.Add(new JoinedTable()
72	96	{
73	97	TableName = "[dbo].[Orders]",
...	...	@@ -93,7 +117,11 @@ public override void PreExecuteReportSet(ReportSet reportSet) {
93	117	``` visualbasic
94	118	Public Overrides Sub PreExecuteReportSet(ByVal reportSet As ReportSet)
95	119	MyBase.PreExecuteReportSet(reportSet)
96		- AdHocContext.Driver.RemoveConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]")
	120	+ oldDriver = AdHocContext.Driver
	121	+ AdHocContext.Driver = new MSSQLDriver(AdHocSettings.SqlServerConnectionString) 'Set the specific type of driver we were using before
	122	+ AdHocSettings.VisibleDataSources = New string() { "[dbo].[Orders]", [dbo].[Suppliers]", "[dbo].[testcon]" } 'testcon is the name of the middle table we want to join with
	123	+ AdHocContext.Driver.AddConstraint("[dbo].[Orders].[OrderID]", "[dbo].[testcon].[ordernum]")
	124	+ AdHocContext.Driver.AddConstraint("[dbo].[Suppliers].[SupplierID]", "[dbo].[testcon].[supplier]") 'Add the correct constraints to the driver
97	125	If (reportSet.JoinedTables.Count > 0) Then
98	126	Dim jts As IEnumerable(Of JoinedTable) = (From jt As JoinedTable In reportSet.JoinedTables
99	127	Where (jt.DbTable.Name.Contains("Orders") OrElse jt.DbTable.Name.Contains("Suppliers")) OrElse
...	...	@@ -128,22 +156,22 @@ End Sub
128	156
129	157	The above code in the [[PreExecuteReportSet()\|/FAQ/PreExecuteReportSet]] method will re-define the relationship between the two tables in a many-to-many relationship and insert the connector table silently. This will produce a working join on the two tables while leaving out the pre-defined fake join. The user will be able to freely select the two tables in the many-to-many relationship without seeing the connecting table.
130	158
131		-Finally, we need a statement in the [[PostExecuteReportSet()\|/FAQ/PostExecuteReportSet]] method.
	159	+Finally, we need a statement in the [[PostExecuteReportSet()\|/FAQ/PostExecuteReportSet]] method to reset the driver.
132	160
133	161	``` csharp
134	162	public override void PostExecuteReportSet(ReportSet reportSet)
135	163	{
136	164	base.PostExecuteReportSet(reportSet);
137		- AdHocContext.Driver.AddConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]");
	165	+ AdHocContext.Driver = oldDriver;
138	166	}
139	167	```
140	168
141	169	``` visualbasic
142	170	Public Overrides Sub PostExecuteReportSet(ByVal reportSet As ReportSet)
143	171	MyBase.PostExecuteReportSet(reportSet)
144		- AdHocContext.Driver.AddConstraint("[dbo].[Orders].[ShipName]", "[dbo].[Suppliers].[CompanyName]")
	172	+ AdHocContext.Driver = oldDriver
145	173	End Sub
146	174	```
147	175
148	176
149		-Re-adding the constraint after report execution will ensure that the tables will be selectable again when the user makes subsequent trips to the Report Designer. Other users in the system without the ability to select the datasources in question will not see any change in their current behavior. Report definitions using the relationship will not reflect the internal process. The fake constraint will appear in the definition.
...	...	\ No newline at end of file
	0	+Resetting the driver after report execution will ensure that the tables with no relationship will be selectable again when the user makes subsequent trips to the Report Designer. Other users in the system without the ability to select the datasources in question will not see any change in their current behavior. Report definitions using the relationship will not reflect the internal process. The fake constraint will appear in the definition.
...	...	\ No newline at end of file