Adding schema diagram api. (#2435)

* Adding schema designer files

* More fixes

* Fixing code

* Fixing contracts

* Cleaning up code

* cleaning up code

* Fixing query

* Fixing database for connection

* removing unused file

* Fixing typo

* Making some PR fixes

* reordering enum

* Fixing comments

src/Microsoft.SqlTools.ServiceLayer/HostLoader.cs

@@ -34,6 +34,7 @@
 using Microsoft.SqlTools.ServiceLayer.QueryExecution;
 using Microsoft.SqlTools.ServiceLayer.QueryStore;
 using Microsoft.SqlTools.ServiceLayer.SchemaCompare;
+using Microsoft.SqlTools.ServiceLayer.SchemaDesigner;
 using Microsoft.SqlTools.ServiceLayer.Scripting;
 using Microsoft.SqlTools.ServiceLayer.ServerConfigurations;
 using Microsoft.SqlTools.ServiceLayer.SqlAssessment;
@@ -179,6 +180,9 @@ private static void InitializeRequestHandlersAndServices(ServiceHost serviceHost
             QueryStoreService.Instance.InitializeService(serviceHost);
             serviceProvider.RegisterSingleService(QueryStoreService.Instance);
 
+            SchemaDesignerService.Instance.InitializeService(serviceHost);
+            serviceProvider.RegisterSingleService(SchemaDesignerService.Instance);
+
             serviceHost.InitializeRequestHandlers();
         }
 

src/Microsoft.SqlTools.ServiceLayer/SchemaDesigner/Contracts/Column.cs

@@ -0,0 +1,30 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.SqlTools.ServiceLayer.SchemaDesigner
+{
+    /// <summary>
+    /// Represents a column in an entity
+    /// </summary>
+    public class Column
+    {
+        /// <summary>
+        /// Gets or sets the name of the column
+        /// </summary>
+        public string Name { get; set; }
+        /// <summary>
+        /// Gets or sets the data type of the column
+        /// </summary>
+        public string DataType { get; set; }
+        /// <summary>
+        /// Gets or sets if the column is a primary key
+        /// </summary>
+        public bool IsPrimaryKey { get; set; }
+        /// <summary>
+        /// Gets or sets if the column is an identity column
+        /// </summary>
+        public bool IsIdentity { get; set; }
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/SchemaDesigner/Contracts/Entity.cs

@@ -0,0 +1,16 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Generic;
+
+namespace Microsoft.SqlTools.ServiceLayer.SchemaDesigner
+{
+    public class Entity
+    {
+        public string Name { get; set; }
+        public string Schema { get; set; }
+        public List<Column> Columns { get; set; }
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/SchemaDesigner/Contracts/GetSchemaModelRequest.cs

@@ -0,0 +1,30 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlTools.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.SchemaDesigner
+{
+    public class GetSchemaModelRequestParams
+    {
+        /// <summary>
+        /// URI identifying the connection to perform the action on. Generally the connection is picked from an existing OE connection.
+        /// </summary>
+        public string ConnectionUri { get; set; }
+        /// <summary>
+        /// Gets or sets the name of the database. Database name is required to get the schema model for the database.
+        /// </summary>
+        public string DatabaseName { get; set; }
+    }
+    /// <summary>
+    /// Request to get the schema model
+    /// </summary>
+    public class GetSchemaModelRequest
+    {
+        public static readonly
+            RequestType<GetSchemaModelRequestParams, SchemaModel> Type =
+            RequestType<GetSchemaModelRequestParams, SchemaModel>.Create("schemaDesigner/getSchemaModel");
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/SchemaDesigner/Contracts/Relationship.cs

@@ -0,0 +1,67 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.SqlTools.ServiceLayer.SchemaDesigner
+{
+    public class Relationship
+    {
+        /// <summary>
+        /// Gets or sets the name of the foreign key
+        /// </summary>
+        public string ForeignKeyName { get; set; }
+        /// <summary>
+        /// Gets or sets the schema name
+        /// </summary>
+        public string SchemaName { get; set; }
+        /// <summary>
+        /// Gets or sets the parent entity (Table in MSSQL) name.
+        /// </summary>
+        public string Entity { get; set; }
+        /// <summary>
+        /// Gets or sets the parent column
+        /// </summary>
+        public string Column { get; set; }
+        /// <summary>
+        /// Gets or sets the referenced schema
+        /// </summary>
+        public string ReferencedSchema { get; set; }
+        /// <summary>
+        /// Gets or sets the referenced entity (Table in MSSQL) name.
+        /// </summary>
+        public string ReferencedEntity { get; set; }
+        /// <summary>
+        /// Gets or sets the referenced column
+        /// </summary>
+        public string ReferencedColumn { get; set; }
+        /// <summary>
+        /// Gets or sets the delete cascade action. Default is NO_ACTION
+        /// </summary>
+        public OnAction OnDeleteAction { get; set; }
+        /// <summary>
+        /// Gets or sets the update cascade action. Default is NO_ACTION
+        /// </summary>
+        public OnAction OnUpdateAction { get; set; }
+    }
+
+    public enum OnAction
+    {
+        /// <summary>
+        /// No action. Do not allow the delete or update of the row from the parent table if there are matching rows in the child table.
+        /// </summary>
+        NO_ACTION = 0,
+        /// <summary>
+        /// Cascade action. Delete or update the row from the parent table and automatically delete or update the matching rows in the child table.
+        /// </summary>
+        CASCADE = 1,
+        /// <summary>
+        /// Set null action. Delete or update the row from the parent table and set the foreign key column or columns in the child table to NULL.
+        /// </summary>
+        SET_NULL = 2,
+        /// <summary>
+        /// Set default action. Delete or update the row from the parent table and set the foreign key column or columns in the child table to their default values.
+        /// </summary>
+        SET_DEFAULT = 3
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/SchemaDesigner/Contracts/SchemaModel.cs

@@ -0,0 +1,21 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Generic;
+
+namespace Microsoft.SqlTools.ServiceLayer.SchemaDesigner
+{
+    public class SchemaModel
+    {
+        /// <summary>
+        /// Gets or sets the entities (Table in MSSQL) in the schema
+        /// </summary>
+        public List<Entity> Entities { get; set; }
+        /// <summary>
+        /// Gets or sets the relationships in the schema
+        /// </summary>
+        public List<Relationship> Relationships { get; set; }
+    }
+}