added marr.datamapper source code for easy debugging.

Marr.Data/QGen/RowCountQueryDecorator.cs

@@ -0,0 +1,127 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Marr.Data.QGen
+{
+    public class RowCountQueryDecorator : IQuery
+    {
+        private SelectQuery _innerQuery;
+
+        public RowCountQueryDecorator(SelectQuery innerQuery)
+        {
+            _innerQuery = innerQuery;
+        }
+        
+        public string Generate()
+        {
+            // Decide which type of paging query to create
+            if (_innerQuery.IsView || _innerQuery.IsJoin)
+            {
+                return ComplexRowCount();
+            }
+            else
+            {
+                return SimpleRowCount();
+            }
+        }
+
+        /// <summary>
+        /// Generates a row count query for a multiple table joined query (groups by the parent entity).
+        /// </summary>
+        /// <returns></returns>
+        private string ComplexRowCount()
+        {
+            // Create paged query
+            StringBuilder sql = new StringBuilder();
+
+            sql.AppendLine("WITH GroupCTE AS (");
+            sql.Append("SELECT ").AppendLine(BuildBaseTablePKColumns());
+            BuildGroupColumn(sql);
+            _innerQuery.BuildFromClause(sql);
+            _innerQuery.BuildJoinClauses(sql);
+            _innerQuery.BuildWhereClause(sql);
+            sql.AppendLine(")");
+            BuildSelectCountClause(sql);
+            sql.AppendLine("FROM GroupCTE");
+            sql.AppendLine("WHERE GroupRow = 1");
+
+            return sql.ToString();
+        }
+
+        /// <summary>
+        /// Generates a row count query for a single table query (no joins).
+        /// </summary>
+        /// <returns></returns>
+        private string SimpleRowCount()
+        {
+            StringBuilder sql = new StringBuilder();
+
+            BuildSelectCountClause(sql);
+            _innerQuery.BuildFromClause(sql);
+            _innerQuery.BuildJoinClauses(sql);
+            _innerQuery.BuildWhereClause(sql);
+
+            return sql.ToString();
+        }
+
+        private void BuildGroupColumn(StringBuilder sql)
+        {
+            string baseTablePKColumns = BuildBaseTablePKColumns();
+            sql.AppendFormat(", ROW_NUMBER() OVER (PARTITION BY {0} ORDER BY {1}) As GroupRow ", baseTablePKColumns, baseTablePKColumns);
+        }
+
+        private string BuildBaseTablePKColumns()
+        {
+            Table baseTable = GetBaseTable();
+
+            StringBuilder sb = new StringBuilder();
+            foreach (var col in baseTable.Columns.PrimaryKeys)
+            {
+                if (sb.Length > 0)
+                    sb.AppendLine(", ");
+
+                string colName = _innerQuery.IsView ?
+                    _innerQuery.NameOrAltName(col.ColumnInfo) :
+                    col.ColumnInfo.Name;
+
+                sb.AppendFormat(_innerQuery.Dialect.CreateToken(string.Concat(baseTable.Alias, ".", colName)));
+            }
+
+            return sb.ToString();
+        }
+
+        private void BuildSelectCountClause(StringBuilder sql)
+        {
+            sql.AppendLine("SELECT COUNT(*)");
+        }
+
+        private Table GetBaseTable()
+        {
+            Table baseTable = null;
+            if (_innerQuery.Tables[0] is View)
+            {
+                baseTable = (_innerQuery.Tables[0] as View).Tables[0];
+            }
+            else
+            {
+                baseTable = _innerQuery.Tables[0];
+            }
+            return baseTable;
+        }
+    }
+}
+
+/*
+WITH GroupCTE AS 
+(
+	SELECT [t0].[ID],[t0].[OrderName],[t1].[ID] AS OrderItemID,[t1].[OrderID],[t1].[ItemDescription],[t1].[Price], 
+	ROW_NUMBER() OVER (PARTITION BY [t0].[ID]  ORDER BY [t0].[OrderName]) As GroupRow  
+	FROM [Order] [t0] 
+	LEFT JOIN [OrderItem] [t1] ON (([t0].[ID] = [t1].[OrderID])) 
+	--WHERE (([t0].[OrderName] = @P0))
+)
+SELECT * FROM GroupCTE
+WHERE GroupRow = 1
+*/