DynamicUpdateCommand.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Map / Update / Internal / DynamicUpdateCommand.cs / 1305376 / DynamicUpdateCommand.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

 
using System.Collections.Generic;
using System.Data.Common.CommandTrees;
using System.Data.Metadata.Edm;
using System.Data.Common; 
using System.Data.EntityClient;
using System.Diagnostics; 
using System.Data.Common.Utils; 
using System.Linq;
using System.Data.Common.CommandTrees.ExpressionBuilder; 
namespace System.Data.Mapping.Update.Internal
{
    internal sealed class DynamicUpdateCommand : UpdateCommand
    { 
        private readonly ModificationOperator m_operator;
        private readonly TableChangeProcessor m_processor; 
        private readonly List> m_inputIdentifiers; 
        private readonly Dictionary m_outputIdentifiers;
        private readonly DbModificationCommandTree m_modificationCommandTree; 


        internal DynamicUpdateCommand(TableChangeProcessor processor, UpdateTranslator translator, ModificationOperator op,
            PropagatorResult originalValues, PropagatorResult currentValues, DbModificationCommandTree tree, 
            Dictionary outputIdentifiers)
            : base(originalValues, currentValues) 
        { 
            m_processor = EntityUtil.CheckArgumentNull(processor, "processor");
            m_operator = op; 
            m_modificationCommandTree = EntityUtil.CheckArgumentNull(tree, "commandTree");
            m_outputIdentifiers = outputIdentifiers; // may be null (not all commands have output identifiers)

            // initialize identifier information (supports lateral propagation of server gen values) 
            if (ModificationOperator.Insert == op || ModificationOperator.Update == op)
            { 
                const int capacity = 2; // "average" number of identifiers per row 
                m_inputIdentifiers = new List>(capacity);
 
                foreach (KeyValuePair member in
                    Helper.PairEnumerations(TypeHelpers.GetAllStructuralMembers(this.CurrentValues.StructuralType),
                                             this.CurrentValues.GetMemberValues()))
                { 
                    DbSetClause setter;
                    int identifier = member.Value.Identifier; 
 
                    if (PropagatorResult.NullIdentifier != identifier &&
                        TryGetSetterExpression(tree, member.Key, op, out setter)) // can find corresponding setter 
                    {
                        foreach (int principal in translator.KeyManager.GetPrincipals(identifier))
                        {
                            m_inputIdentifiers.Add(new KeyValuePair(principal, setter)); 
                        }
                    } 
                } 
            }
        } 

        // effects: try to find setter expression for the given member
        // requires: command tree must be an insert or update tree (since other DML trees hnabve
        private static bool TryGetSetterExpression(DbModificationCommandTree tree, EdmMember member, ModificationOperator op, out DbSetClause setter) 
        {
            Debug.Assert(op == ModificationOperator.Insert || op == ModificationOperator.Update, "only inserts and updates have setters"); 
            IEnumerable clauses; 
            if (ModificationOperator.Insert == op)
            { 
                clauses = ((DbInsertCommandTree)tree).SetClauses;
            }
            else
            { 
                clauses = ((DbUpdateCommandTree)tree).SetClauses;
            } 
            foreach (DbSetClause setClause in clauses) 
            {
                // check if this is the correct setter 
                if (((DbPropertyExpression)setClause.Property).Property.EdmEquals(member))
                {
                    setter = setClause;
                    return true; 
                }
            } 
 
            // no match found
            setter = null; 
            return false;
        }

        internal override long Execute(UpdateTranslator translator, EntityConnection connection, Dictionary identifierValues, List> generatedValues) 
        {
            // Compile command 
            DbCommand command = this.CreateCommand(translator, identifierValues); 

            // configure command to use the connection and transaction for this session 
            command.Transaction = ((null != connection.CurrentTransaction) ? connection.CurrentTransaction.StoreTransaction : null);
            command.Connection = connection.StoreConnection;
            if (translator.CommandTimeout.HasValue)
            { 
                command.CommandTimeout = translator.CommandTimeout.Value;
            } 
 
            // Execute the query
            int rowsAffected; 
            if (m_modificationCommandTree.HasReader)
            {
                // retrieve server gen results
                rowsAffected = 0; 
                using (DbDataReader reader = command.ExecuteReader(CommandBehavior.SequentialAccess))
                { 
                    if (reader.Read()) 
                    {
                        rowsAffected++; 

                        IBaseList members = TypeHelpers.GetAllStructuralMembers(this.CurrentValues.StructuralType);

                        for (int ordinal = 0; ordinal < reader.FieldCount; ordinal++) 
                        {
                            // column name of result corresponds to column name of table 
                            string columnName = reader.GetName(ordinal); 
                            object value = reader.GetValue(ordinal);
 
                            // retrieve result which includes the context for back-propagation
                            int columnOrdinal = members.IndexOf(members[columnName]);
                            PropagatorResult result = this.CurrentValues.GetMemberValue(columnOrdinal);
 
                            // register for back-propagation
                            generatedValues.Add(new KeyValuePair(result, value)); 
 
                            // register identifier if it exists
                            int identifier = result.Identifier; 
                            if (PropagatorResult.NullIdentifier != identifier)
                            {
                                identifierValues.Add(identifier, value);
                            } 
                        }
                    } 
 
                    // Consume the current reader (and subsequent result sets) so that any errors
                    // executing the command can be intercepted 
                    CommandHelper.ConsumeReader(reader);
                }
            }
            else 
            {
                rowsAffected = command.ExecuteNonQuery(); 
            } 
            return rowsAffected;
        } 

        /// 
        /// Gets DB command definition encapsulating store logic for this command.
        ///  
        private DbCommand CreateCommand(UpdateTranslator translator, Dictionary identifierValues)
        { 
            DbModificationCommandTree commandTree = m_modificationCommandTree; 

            // check if any server gen identifiers need to be set 
            if (null != m_inputIdentifiers)
            {
                Dictionary modifiedClauses = new Dictionary();
                for (int idx = 0; idx < m_inputIdentifiers.Count; idx++) 
                {
                    KeyValuePair inputIdentifier = m_inputIdentifiers[idx]; 
 
                    object value;
                    if (identifierValues.TryGetValue(inputIdentifier.Key, out value)) 
                    {
                        // reset the value of the identifier
                        DbSetClause newClause = new DbSetClause(inputIdentifier.Value.Property, DbExpressionBuilder.Constant(value));
                        modifiedClauses[inputIdentifier.Value] = newClause; 
                        m_inputIdentifiers[idx] = new KeyValuePair(inputIdentifier.Key, newClause);
                    } 
                } 
                commandTree = RebuildCommandTree(commandTree, modifiedClauses);
            } 

            return translator.CreateCommand(commandTree);
        }
 
        private DbModificationCommandTree RebuildCommandTree(DbModificationCommandTree originalTree, Dictionary clauseMappings)
        { 
            if (clauseMappings.Count == 0) 
            {
                return originalTree; 
            }

            DbModificationCommandTree result;
            Debug.Assert(originalTree.CommandTreeKind == DbCommandTreeKind.Insert || originalTree.CommandTreeKind == DbCommandTreeKind.Update, "Set clauses specified for a modification tree that is not an update or insert tree?"); 
            if (originalTree.CommandTreeKind == DbCommandTreeKind.Insert)
            { 
                DbInsertCommandTree insertTree = (DbInsertCommandTree)originalTree; 
                result = new DbInsertCommandTree(insertTree.MetadataWorkspace, insertTree.DataSpace,
                    insertTree.Target, ReplaceClauses(insertTree.SetClauses, clauseMappings).AsReadOnly(), insertTree.Returning); 
            }
            else
            {
                DbUpdateCommandTree updateTree = (DbUpdateCommandTree)originalTree; 
                result = new DbUpdateCommandTree(updateTree.MetadataWorkspace, updateTree.DataSpace,
                    updateTree.Target, updateTree.Predicate, ReplaceClauses(updateTree.SetClauses, clauseMappings).AsReadOnly(), updateTree.Returning); 
            } 

            return result; 
        }

        /// 
        /// Creates a new list of modification clauses with the specified remapped clauses replaced. 
        /// 
        private List ReplaceClauses(IList originalClauses, Dictionary mappings) 
        { 
            List result = new List(originalClauses.Count);
            for (int idx = 0; idx < originalClauses.Count; idx++) 
            {
                DbSetClause replacementClause;
                if (mappings.TryGetValue((DbSetClause)originalClauses[idx], out replacementClause))
                { 
                    result.Add(replacementClause);
                } 
                else 
                {
                    result.Add(originalClauses[idx]); 
                }
            }
            return result;
        } 

        internal ModificationOperator Operator { get { return m_operator; } } 
 
        internal override EntitySet Table { get { return this.m_processor.Table; } }
 
        internal override IEnumerable InputIdentifiers
        {
            get
            { 
                if (null == m_inputIdentifiers)
                { 
                    yield break; 
                }
                else 
                {
                    foreach (KeyValuePair inputIdentifier in m_inputIdentifiers)
                    {
                        yield return inputIdentifier.Key; 
                    }
                } 
            } 
        }
 
        internal override IEnumerable OutputIdentifiers
        {
            get
            { 
                if (null == m_outputIdentifiers)
                { 
                    return Enumerable.Empty(); 
                }
                return m_outputIdentifiers.Keys; 
            }
        }

        internal override UpdateCommandKind Kind 
        {
            get { return UpdateCommandKind.Dynamic; } 
        } 

        internal override IList GetStateEntries(UpdateTranslator translator) 
        {
            List stateEntries = new List(2);
            if (null != this.OriginalValues)
            { 
                foreach (IEntityStateEntry stateEntry in SourceInterpreter.GetAllStateEntries(
                    this.OriginalValues, translator, this.Table)) 
                { 
                    stateEntries.Add(stateEntry);
                } 
            }

            if (null != this.CurrentValues)
            { 
                foreach (IEntityStateEntry stateEntry in SourceInterpreter.GetAllStateEntries(
                    this.CurrentValues, translator, this.Table)) 
                { 
                    stateEntries.Add(stateEntry);
                } 
            }
            return stateEntries;
        }
 
        internal override int CompareToType(UpdateCommand otherCommand)
        { 
            Debug.Assert(!object.ReferenceEquals(this, otherCommand), "caller is supposed to ensure otherCommand is different reference"); 

            DynamicUpdateCommand other = (DynamicUpdateCommand)otherCommand; 

            // order by operation type
            int result = (int)this.Operator - (int)other.Operator;
            if (0 != result) { return result; } 

            // order by Container.Table 
            result = StringComparer.Ordinal.Compare(this.m_processor.Table.Name, other.m_processor.Table.Name); 
            if (0 != result) { return result; }
            result = StringComparer.Ordinal.Compare(this.m_processor.Table.EntityContainer.Name, other.m_processor.Table.EntityContainer.Name); 
            if (0 != result) { return result; }

            // order by table key
            PropagatorResult thisResult = (this.Operator == ModificationOperator.Delete ? this.OriginalValues : this.CurrentValues); 
            PropagatorResult otherResult = (other.Operator == ModificationOperator.Delete ? other.OriginalValues : other.CurrentValues);
            for (int i = 0; i < m_processor.KeyOrdinals.Length; i++) 
            { 
                int keyOrdinal = m_processor.KeyOrdinals[i];
                object thisValue = thisResult.GetMemberValue(keyOrdinal).GetSimpleValue(); 
                object otherValue = otherResult.GetMemberValue(keyOrdinal).GetSimpleValue();
                result = ByValueComparer.Default.Compare(thisValue, otherValue);
                if (0 != result) { return result; }
            } 

            // If the result is still zero, it means key values are all the same. Switch to synthetic identifiers 
            // to differentiate. 
            for (int i = 0; i < m_processor.KeyOrdinals.Length; i++)
            { 
                int keyOrdinal = m_processor.KeyOrdinals[i];
                int thisValue = thisResult.GetMemberValue(keyOrdinal).Identifier;
                int otherValue = otherResult.GetMemberValue(keyOrdinal).Identifier;
                result = thisValue - otherValue; 
                if (0 != result) { return result; }
            } 
 
            return result;
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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DynamicUpdateCommand.cs source code in C# .NET

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