Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / Filter / AggregateNode.cs / 4 / AggregateNode.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //[....] //----------------------------------------------------------------------------- namespace System.Data { using System; using System.Diagnostics; using System.Collections.Generic; using System.ComponentModel; internal enum Aggregate { None = FunctionId.none, Sum = FunctionId.Sum, Avg = FunctionId.Avg, Min = FunctionId.Min, Max = FunctionId.Max, Count = FunctionId.Count, StDev = FunctionId.StDev, // Statistical standard deviation Var = FunctionId.Var, // Statistical variance } internal sealed class AggregateNode : ExpressionNode { private readonly AggregateType type; private readonly Aggregate aggregate; private readonly bool local; // set to true if the aggregate calculated localy (for the current table) private readonly string relationName; private readonly string columnName; // private DataTable childTable; private DataColumn column; private DataRelation relation; internal AggregateNode(DataTable table, FunctionId aggregateType, string columnName) : this(table, aggregateType, columnName, true, null) { } internal AggregateNode(DataTable table, FunctionId aggregateType, string columnName, string relationName) : this(table, aggregateType, columnName, false, relationName) { } internal AggregateNode(DataTable table, FunctionId aggregateType, string columnName, bool local, string relationName) : base(table) { Debug.Assert(columnName != null, "Invalid parameter column name (null)."); this.aggregate = (Aggregate)(int)aggregateType; if (aggregateType == FunctionId.Sum) this.type = AggregateType.Sum; else if (aggregateType == FunctionId.Avg) this.type = AggregateType.Mean; else if (aggregateType == FunctionId.Min) this.type = AggregateType.Min; else if (aggregateType == FunctionId.Max) this.type = AggregateType.Max; else if (aggregateType == FunctionId.Count) this.type = AggregateType.Count; else if (aggregateType == FunctionId.Var) this.type = AggregateType.Var; else if (aggregateType == FunctionId.StDev) this.type = AggregateType.StDev; else { throw ExprException.UndefinedFunction(Function.FunctionName[(Int32)aggregateType]); } this.local = local; this.relationName = relationName; this.columnName = columnName; } internal override void Bind(DataTable table, Listlist) { BindTable(table); if (table == null) throw ExprException.AggregateUnbound(this.ToString()); if (local) { relation = null; } else { DataRelationCollection relations; relations = table.ChildRelations; if (relationName == null) { // must have one and only one relation if (relations.Count > 1) { throw ExprException.UnresolvedRelation(table.TableName, this.ToString()); } if (relations.Count == 1) { relation = relations[0]; } else { throw ExprException.AggregateUnbound(this.ToString()); } } else { relation = relations[relationName]; } } childTable = (relation == null) ? table : relation.ChildTable; this.column = childTable.Columns[columnName]; if (column == null) throw ExprException.UnboundName(columnName); // add column to the dependency list, do not add duplicate columns Debug.Assert(column != null, "Failed to bind column " + columnName); int i; for (i = 0; i < list.Count; i++) { // walk the list, check if the current column already on the list DataColumn dataColumn = (DataColumn)list[i]; if (column == dataColumn) { break; } } if (i >= list.Count) { list.Add(column); } // AggregateNode.Bind(relation, list); } internal static void Bind(DataRelation relation, List list) { if (null != relation) { // add the ends of the relationship the expression depends on foreach (DataColumn c in relation.ChildColumnsReference) { if (!list.Contains(c)) { list.Add(c); } } foreach (DataColumn c in relation.ParentColumnsReference) { if (!list.Contains(c)) { list.Add(c); } } } } internal override object Eval() { return Eval(null, DataRowVersion.Default); } internal override object Eval(DataRow row, DataRowVersion version) { if (childTable == null) throw ExprException.AggregateUnbound(this.ToString()); DataRow[] rows; if (local) { rows = new DataRow[childTable.Rows.Count]; childTable.Rows.CopyTo(rows, 0); } else { if (row == null) { throw ExprException.EvalNoContext(); } if (relation == null) { throw ExprException.AggregateUnbound(this.ToString()); } rows = row.GetChildRows(relation, version); } int[] records; if (version == DataRowVersion.Proposed) { version = DataRowVersion.Default; } List recordList = new List (); for (int i = 0; i < rows.Length; i++) { if (rows[i].RowState == DataRowState.Deleted) { if (DataRowAction.Rollback != rows[i]._action) { continue; } Debug.Assert(DataRowVersion.Original == version, "wrong version"); version = DataRowVersion.Original; } else if ((DataRowAction.Rollback == rows[i]._action) && (rows[i].RowState == DataRowState.Added)) { continue; // WebData 91297 } if (version == DataRowVersion.Original && rows[i].oldRecord == -1) { continue; } recordList.Add(rows[i].GetRecordFromVersion(version)); } records = recordList.ToArray(); return column.GetAggregateValue(records, type); } // Helper for the DataTable.Compute method internal override object Eval(int[] records) { if (childTable == null) throw ExprException.AggregateUnbound(this.ToString()); if (!local) { throw ExprException.ComputeNotAggregate(this.ToString()); } return column.GetAggregateValue(records, type); } internal override bool IsConstant() { return false; } internal override bool IsTableConstant() { return local; } internal override bool HasLocalAggregate() { return local; } internal override bool HasRemoteAggregate() { return !local; } internal override bool DependsOn(DataColumn column) { if (this.column == column) { return true; } if (this.column.Computed) { return this.column.DataExpression.DependsOn(column); } return false; } internal override ExpressionNode Optimize() { return this; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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