Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / ndp / fx / src / DataEntity / System / Data / Map / Update / Internal / UpdateCompiler.cs / 2 / UpdateCompiler.cs
//----------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//
// @owner [....]
// @backupOwner [....]
//---------------------------------------------------------------------
using System.Data.Metadata.Edm;
// For the purposes of the update compiler, the member name fully describes the member
// within the table entity set.
// It's convenient to use 'string' to represent the member, because it allows us to
// painlessly associate members of the transient extent (the table in C-Space) with
// the real extent (the table in S-Space).
using System.Data.Common;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Globalization;
using System.Data.Common.Utils;
using System.Data.SqlClient.SqlGen;
using System.Data.Common.CommandTrees;
using System.Data.Entity;
namespace System.Data.Mapping.Update.Internal
{
///
/// This class implements compilation of DML operation requests to some
/// format (e.g. canonical query tree or T-SQL)
///
internal sealed class UpdateCompiler
{
#region Constructors
///
/// Initialize an update compiler.
///
/// Update context.
internal UpdateCompiler(UpdateTranslator translator)
{
m_translator = translator;
}
#endregion
#region Fields
internal readonly UpdateTranslator m_translator;
private const string s_targetVarName = "target";
#endregion
///
/// Builds a delete command.
///
/// Value of the row being deleted.
/// Context for the table containing row.
/// Delete command.
internal UpdateCommand BuildDeleteCommand(PropagatorResult oldRow, TableChangeProcessor processor)
{
// If we're deleting a row, the row must always be touched
bool rowMustBeTouched = true;
// Initialize DML command tree
DbDeleteCommandTree commandTree = new DbDeleteCommandTree(m_translator.MetadataWorkspace, DataSpace.CSpace);
SetTarget(processor, commandTree);
// Create delete predicate
commandTree.Predicate = BuildPredicate(commandTree, oldRow, null, processor, ref rowMustBeTouched);
// Set command
// Initialize delete command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Delete, oldRow, null, commandTree, null);
return command;
}
///
/// Builds an update command.
///
/// Old value of the row being updated.
/// New value for the row being updated.
/// Context for the table containing row.
/// Update command.
internal UpdateCommand BuildUpdateCommand(PropagatorResult oldRow,
PropagatorResult newRow, TableChangeProcessor processor)
{
// If we're updating a row, the row may not need to be touched (e.g., no concurrency validation required)
bool rowMustBeTouched = false;
// Initialize DML command tree
DbUpdateCommandTree commandTree = new DbUpdateCommandTree(m_translator.MetadataWorkspace, DataSpace.CSpace);
SetTarget(processor, commandTree);
// Create update predicate
commandTree.Predicate = BuildPredicate(commandTree, oldRow, newRow, processor, ref rowMustBeTouched);
// Add set clauses
Dictionary outputIdentifiers;
DbExpression returning;
List setClauses = new List();
foreach (DbModificationClause clause in BuildSetClauses(
commandTree, newRow, processor, /* insertMode */ false, out outputIdentifiers, out returning,
ref rowMustBeTouched))
{
setClauses.Add(clause);
}
commandTree.InitializeSetClauses(setClauses);
// Construct predicate identifying the row to modify
commandTree.Predicate = BuildPredicate(commandTree, oldRow, newRow, processor, ref rowMustBeTouched);
// Determine if there is nothing to do (i.e., no values to set,
// no computed columns, and no concurrency validation required)
if (!rowMustBeTouched && 0 == commandTree.SetClauses.Count)
{
return null;
}
// Set the returning parameters
if (null != returning)
{
commandTree.Returning = returning;
}
// Create command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Update, oldRow, newRow, commandTree, outputIdentifiers);
return command;
}
///
/// Builds insert command.
///
/// Row to insert.
/// Context for the table we're inserting into.
/// Insert command.
internal UpdateCommand BuildInsertCommand(PropagatorResult newRow, TableChangeProcessor processor)
{
// Initialize DML command tree
DbInsertCommandTree commandTree = new DbInsertCommandTree(m_translator.MetadataWorkspace, DataSpace.CSpace);
SetTarget(processor, commandTree);
// Add set clauses
Dictionary outputIdentifiers;
DbExpression returning;
bool rowMustBeTouched = true; // for inserts, the row must always be touched
List setClauses = new List();
foreach (DbModificationClause clause in BuildSetClauses(commandTree, newRow, processor, /* insertMode */ true, out outputIdentifiers,
out returning, ref rowMustBeTouched))
{
setClauses.Add(clause);
}
commandTree.InitializeSetClauses(setClauses);
// Set the returning parameters
if (null != returning)
{
commandTree.Returning = returning;
}
// Create command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Insert, null, newRow, commandTree, outputIdentifiers);
return command;
}
///
/// Determines column/value used to set values for a row.
///
///
/// The following columns are not included in the result:
///
/// - Keys (if
/// - Values flagged 'preserve' (these are values the propagator claims are
/// untouched)
/// - Server generated values.
///
///
/// Command tree hosting the set parameters.
/// Row containing values to set.
/// Context for table.
/// Determines whether key columns and 'preserve' columns are
/// omitted from the list.
/// Dictionary listing server generated identifiers.
/// DbExpression describing result projection for server generated values.
/// Indicates whether the row must be touched
/// because it produces a value (e.g. computed)
/// Column value pairs.
private IEnumerable BuildSetClauses(DbModificationCommandTree commandTree, PropagatorResult row,
TableChangeProcessor processor, bool insertMode, out Dictionary outputIdentifiers, out DbExpression returning,
ref bool rowMustBeTouched)
{
Dictionary setClauses = new Dictionary();
List> returningArguments = new List>();
outputIdentifiers = new Dictionary();
// Determine which flags indicate a property should be omitted from the set list.
PropagatorFlags omitMask = insertMode ? PropagatorFlags.NoFlags :
PropagatorFlags.Preserve | PropagatorFlags.Unknown;
for (int propertyOrdinal = 0; propertyOrdinal < processor.Table.ElementType.Properties.Count; propertyOrdinal++)
{
EdmProperty property = processor.Table.ElementType.Properties[propertyOrdinal];
// Type members and result values are ordinally aligned
PropagatorResult propertyResult = row.GetMemberValue(propertyOrdinal);
if (PropagatorResult.NullIdentifier != propertyResult.Identifier)
{
// retrieve principal value
propertyResult = propertyResult.ReplicateResultWithNewValue(
m_translator.KeyManager.GetPrincipalValue(propertyResult));
}
bool omitFromSetList = false;
Debug.Assert(propertyResult.IsSimple);
// Determine if this is a key value
bool isKey = false;
for (int i = 0; i < processor.KeyOrdinals.Length; i++)
{
if (processor.KeyOrdinals[i] == propertyOrdinal)
{
isKey = true;
break;
}
}
// check if this value should be omitted
PropagatorFlags flags = PropagatorFlags.NoFlags;
if (!insertMode && isKey)
{
// Keys are only set for inserts
omitFromSetList = true;
}
else
{
// See if this value has been marked up with some context. If so, add the flag information
// from the markup. Markup includes information about whether the property is a concurrency value,
// whether it is known (it may be a property that is preserved across an update for instance)
flags |= propertyResult.PropagatorFlags;
}
// Determine if this value is server-generated
StoreGeneratedPattern genPattern = MetadataHelper.GetStoreGeneratedPattern(property);
bool isServerGen = genPattern == StoreGeneratedPattern.Computed ||
(insertMode && genPattern == StoreGeneratedPattern.Identity);
if (isServerGen)
{
DbPropertyExpression propertyExpression = commandTree.CreatePropertyExpression(
property, commandTree.Target.Variable);
returningArguments.Add(new KeyValuePair(property.Name, propertyExpression));
// check if this is a server generated identifier
Int64 identifier = propertyResult.Identifier;
if (PropagatorResult.NullIdentifier != identifier)
{
if (m_translator.KeyManager.HasPrincipals(identifier))
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_GeneratedDependent(property.Name));
}
outputIdentifiers.Add(identifier, property.Name);
// If this property maps an identifier (in the update pipeline) it may
// also be a store key. If so, the pattern had better be "Identity"
// since otherwise we're dealing with a mutable key.
if (genPattern != StoreGeneratedPattern.Identity &&
processor.IsKeyProperty(propertyOrdinal))
{
throw EntityUtil.NotSupported(System.Data.Entity.Strings.Update_NotSupportedComputedKeyColumn(
EdmProviderManifest.StoreGeneratedPatternFacetName,
XmlConstants.Computed,
XmlConstants.Identity,
property.Name,
property.DeclaringType.FullName));
}
}
}
if (PropagatorFlags.NoFlags != (flags & (omitMask)))
{
// column value matches "omit" pattern, therefore should not be set
omitFromSetList = true;
}
else if (isServerGen)
{
// column value does not match "omit" pattern, but it is server generated
// so it cannot be set
omitFromSetList = true;
// if the row has a modified value overridden by server gen,
// it must still be touched in order to retrieve the value
rowMustBeTouched = true;
}
// make the user is not updating an identity value
if (!omitFromSetList && !insertMode && genPattern == StoreGeneratedPattern.Identity)
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_ModifyingIdentityColumn(
XmlConstants.Identity,
property.Name,
property.DeclaringType.FullName));
}
if (!omitFromSetList) { setClauses.Add(property, propertyResult); }
}
// Construct returning projection
if (0 < returningArguments.Count)
{
returning = commandTree.CreateNewRowExpression(returningArguments);
}
else
{
returning = null;
}
// Construct clauses corresponding to the set clauses
List result = new List(setClauses.Count);
foreach (KeyValuePair setClause in setClauses)
{
EdmProperty property = setClause.Key;
result.Add(new DbSetClause(commandTree,
GeneratePropertyExpression(commandTree, setClause.Key),
GenerateValueExpression(commandTree, setClause.Key, setClause.Value)));
}
return result;
}
///
/// Determines predicate used to identify a row in a table.
///
///
/// Columns are included in the list when:
///
/// - They are keys for the table
/// - They are concurrency values
///
///
/// Command tree hosting the predicate
/// Values for the row being located.
/// Values being updated (may be null).
/// Context for the table containing the row.
/// Output parameter indicating whether a row must be touched
/// (whether it's being modified or not) because it contains a concurrency value
/// Column/value pairs.
private DbExpression BuildPredicate(DbModificationCommandTree commandTree, PropagatorResult referenceRow, PropagatorResult current,
TableChangeProcessor processor, ref bool rowMustBeTouched)
{
Dictionary whereClauses = new Dictionary();
// add all concurrency tokens (note that keys are always concurrency tokens as well)
int propertyOrdinal = 0;
foreach (EdmProperty member in processor.Table.ElementType.Members)
{
// members and result values are ordinally aligned
PropagatorResult expectedValue = referenceRow.GetMemberValue(propertyOrdinal);
PropagatorResult newValue = null == current ? null : current.GetMemberValue(propertyOrdinal);
// check if the rowMustBeTouched value should be set to true (if it isn't already
// true and we've come across a concurrency value)
if (!rowMustBeTouched &&
(HasFlag(expectedValue, PropagatorFlags.ConcurrencyValue) ||
HasFlag(newValue, PropagatorFlags.ConcurrencyValue)))
{
rowMustBeTouched = true;
}
// determine if this is a concurrency value
if (!whereClauses.ContainsKey(member) && // don't add to the set clause twice
(HasFlag(expectedValue, PropagatorFlags.ConcurrencyValue | PropagatorFlags.Key) ||
HasFlag(newValue, PropagatorFlags.ConcurrencyValue | PropagatorFlags.Key))) // tagged as concurrency value
{
whereClauses.Add(member, expectedValue);
}
propertyOrdinal++;
}
// Build a binary AND expression tree from the clauses
DbExpression predicate = null;
foreach (KeyValuePair clause in whereClauses)
{
DbExpression clauseExpression = GenerateEqualityExpression(commandTree, clause.Key, clause.Value);
if (null == predicate) { predicate = clauseExpression; }
else { predicate = commandTree.CreateAndExpression(predicate, clauseExpression); }
}
Debug.Assert(null != predicate, "some predicate term must exist");
return predicate;
}
// Effects: given a "clause" in the form of a property/value pair, produces an equality expression. If the
// value is null, creates an IsNull expression
// Requires: all arguments are set
private DbExpression GenerateEqualityExpression(DbModificationCommandTree commandTree, EdmProperty property, PropagatorResult value)
{
Debug.Assert(null != commandTree && null != property && null != value);
DbExpression propertyExpression = GeneratePropertyExpression(commandTree, property);
if (value.IsNull)
{
return commandTree.CreateIsNullExpression(propertyExpression);
}
if (!TypeSemantics.IsEqualComparable(property.TypeUsage))
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_NonEquatableColumnTypeInClause(
property.Name, property.DeclaringType.Name));
}
return commandTree.CreateEqualsExpression(propertyExpression, GenerateValueExpression(commandTree, property, value));
}
// Effects: given a property, produces a property expression
// Requires: all arguments are set
private static DbExpression GeneratePropertyExpression(DbModificationCommandTree commandTree, EdmProperty property)
{
Debug.Assert(null != commandTree && null != property);
return commandTree.CreatePropertyExpression(property, commandTree.Target.Variable);
}
// Effects: given a propagator result, produces a constant expression describing that value.
// Requires: all arguments are set, and the value must be simple (scalar)
private DbExpression GenerateValueExpression(DbCommandTree commandTree, EdmProperty property, PropagatorResult value)
{
Debug.Assert(null != commandTree && null != value && value.IsSimple && null != property);
if (value.IsNull)
{
return commandTree.CreateNullExpression(Helper.GetModelTypeUsage(property));
}
object principalValue = m_translator.KeyManager.GetPrincipalValue(value);
return commandTree.CreateConstantExpression(principalValue, Helper.GetModelTypeUsage(property));
}
// Effects: returns true iff. the input propagator result has some flag defined in "flags"
// Requires: input is set
private static bool HasFlag(PropagatorResult input, PropagatorFlags flags)
{
if (null == input) { return false; }
return (PropagatorFlags.NoFlags != (flags & input.PropagatorFlags));
}
// Effects: initializes the target (table being modified) for the given DML command tree according
// to the table managed by the processor.
// Requires: all arguments set
private static void SetTarget(TableChangeProcessor processor, DbModificationCommandTree commandTree)
{
Debug.Assert(null != processor && null != commandTree);
// use a fixed var name since the command trees all have exactly one binding
commandTree.Target = commandTree.CreateExpressionBinding(
commandTree.CreateScanExpression(processor.Table), s_targetVarName);
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//----------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//
// @owner [....]
// @backupOwner [....]
//---------------------------------------------------------------------
using System.Data.Metadata.Edm;
// For the purposes of the update compiler, the member name fully describes the member
// within the table entity set.
// It's convenient to use 'string' to represent the member, because it allows us to
// painlessly associate members of the transient extent (the table in C-Space) with
// the real extent (the table in S-Space).
using System.Data.Common;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Globalization;
using System.Data.Common.Utils;
using System.Data.SqlClient.SqlGen;
using System.Data.Common.CommandTrees;
using System.Data.Entity;
namespace System.Data.Mapping.Update.Internal
{
///
/// This class implements compilation of DML operation requests to some
/// format (e.g. canonical query tree or T-SQL)
///
internal sealed class UpdateCompiler
{
#region Constructors
///
/// Initialize an update compiler.
///
/// Update context.
internal UpdateCompiler(UpdateTranslator translator)
{
m_translator = translator;
}
#endregion
#region Fields
internal readonly UpdateTranslator m_translator;
private const string s_targetVarName = "target";
#endregion
///
/// Builds a delete command.
///
/// Value of the row being deleted.
/// Context for the table containing row.
/// Delete command.
internal UpdateCommand BuildDeleteCommand(PropagatorResult oldRow, TableChangeProcessor processor)
{
// If we're deleting a row, the row must always be touched
bool rowMustBeTouched = true;
// Initialize DML command tree
DbDeleteCommandTree commandTree = new DbDeleteCommandTree(m_translator.MetadataWorkspace, DataSpace.CSpace);
SetTarget(processor, commandTree);
// Create delete predicate
commandTree.Predicate = BuildPredicate(commandTree, oldRow, null, processor, ref rowMustBeTouched);
// Set command
// Initialize delete command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Delete, oldRow, null, commandTree, null);
return command;
}
///
/// Builds an update command.
///
/// Old value of the row being updated.
/// New value for the row being updated.
/// Context for the table containing row.
/// Update command.
internal UpdateCommand BuildUpdateCommand(PropagatorResult oldRow,
PropagatorResult newRow, TableChangeProcessor processor)
{
// If we're updating a row, the row may not need to be touched (e.g., no concurrency validation required)
bool rowMustBeTouched = false;
// Initialize DML command tree
DbUpdateCommandTree commandTree = new DbUpdateCommandTree(m_translator.MetadataWorkspace, DataSpace.CSpace);
SetTarget(processor, commandTree);
// Create update predicate
commandTree.Predicate = BuildPredicate(commandTree, oldRow, newRow, processor, ref rowMustBeTouched);
// Add set clauses
Dictionary outputIdentifiers;
DbExpression returning;
List setClauses = new List();
foreach (DbModificationClause clause in BuildSetClauses(
commandTree, newRow, processor, /* insertMode */ false, out outputIdentifiers, out returning,
ref rowMustBeTouched))
{
setClauses.Add(clause);
}
commandTree.InitializeSetClauses(setClauses);
// Construct predicate identifying the row to modify
commandTree.Predicate = BuildPredicate(commandTree, oldRow, newRow, processor, ref rowMustBeTouched);
// Determine if there is nothing to do (i.e., no values to set,
// no computed columns, and no concurrency validation required)
if (!rowMustBeTouched && 0 == commandTree.SetClauses.Count)
{
return null;
}
// Set the returning parameters
if (null != returning)
{
commandTree.Returning = returning;
}
// Create command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Update, oldRow, newRow, commandTree, outputIdentifiers);
return command;
}
///
/// Builds insert command.
///
/// Row to insert.
/// Context for the table we're inserting into.
/// Insert command.
internal UpdateCommand BuildInsertCommand(PropagatorResult newRow, TableChangeProcessor processor)
{
// Initialize DML command tree
DbInsertCommandTree commandTree = new DbInsertCommandTree(m_translator.MetadataWorkspace, DataSpace.CSpace);
SetTarget(processor, commandTree);
// Add set clauses
Dictionary outputIdentifiers;
DbExpression returning;
bool rowMustBeTouched = true; // for inserts, the row must always be touched
List setClauses = new List();
foreach (DbModificationClause clause in BuildSetClauses(commandTree, newRow, processor, /* insertMode */ true, out outputIdentifiers,
out returning, ref rowMustBeTouched))
{
setClauses.Add(clause);
}
commandTree.InitializeSetClauses(setClauses);
// Set the returning parameters
if (null != returning)
{
commandTree.Returning = returning;
}
// Create command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Insert, null, newRow, commandTree, outputIdentifiers);
return command;
}
///
/// Determines column/value used to set values for a row.
///
///
/// The following columns are not included in the result:
///
/// - Keys (if
/// - Values flagged 'preserve' (these are values the propagator claims are
/// untouched)
/// - Server generated values.
///
///
/// Command tree hosting the set parameters.
/// Row containing values to set.
/// Context for table.
/// Determines whether key columns and 'preserve' columns are
/// omitted from the list.
/// Dictionary listing server generated identifiers.
/// DbExpression describing result projection for server generated values.
/// Indicates whether the row must be touched
/// because it produces a value (e.g. computed)
/// Column value pairs.
private IEnumerable BuildSetClauses(DbModificationCommandTree commandTree, PropagatorResult row,
TableChangeProcessor processor, bool insertMode, out Dictionary outputIdentifiers, out DbExpression returning,
ref bool rowMustBeTouched)
{
Dictionary setClauses = new Dictionary();
List> returningArguments = new List>();
outputIdentifiers = new Dictionary();
// Determine which flags indicate a property should be omitted from the set list.
PropagatorFlags omitMask = insertMode ? PropagatorFlags.NoFlags :
PropagatorFlags.Preserve | PropagatorFlags.Unknown;
for (int propertyOrdinal = 0; propertyOrdinal < processor.Table.ElementType.Properties.Count; propertyOrdinal++)
{
EdmProperty property = processor.Table.ElementType.Properties[propertyOrdinal];
// Type members and result values are ordinally aligned
PropagatorResult propertyResult = row.GetMemberValue(propertyOrdinal);
if (PropagatorResult.NullIdentifier != propertyResult.Identifier)
{
// retrieve principal value
propertyResult = propertyResult.ReplicateResultWithNewValue(
m_translator.KeyManager.GetPrincipalValue(propertyResult));
}
bool omitFromSetList = false;
Debug.Assert(propertyResult.IsSimple);
// Determine if this is a key value
bool isKey = false;
for (int i = 0; i < processor.KeyOrdinals.Length; i++)
{
if (processor.KeyOrdinals[i] == propertyOrdinal)
{
isKey = true;
break;
}
}
// check if this value should be omitted
PropagatorFlags flags = PropagatorFlags.NoFlags;
if (!insertMode && isKey)
{
// Keys are only set for inserts
omitFromSetList = true;
}
else
{
// See if this value has been marked up with some context. If so, add the flag information
// from the markup. Markup includes information about whether the property is a concurrency value,
// whether it is known (it may be a property that is preserved across an update for instance)
flags |= propertyResult.PropagatorFlags;
}
// Determine if this value is server-generated
StoreGeneratedPattern genPattern = MetadataHelper.GetStoreGeneratedPattern(property);
bool isServerGen = genPattern == StoreGeneratedPattern.Computed ||
(insertMode && genPattern == StoreGeneratedPattern.Identity);
if (isServerGen)
{
DbPropertyExpression propertyExpression = commandTree.CreatePropertyExpression(
property, commandTree.Target.Variable);
returningArguments.Add(new KeyValuePair(property.Name, propertyExpression));
// check if this is a server generated identifier
Int64 identifier = propertyResult.Identifier;
if (PropagatorResult.NullIdentifier != identifier)
{
if (m_translator.KeyManager.HasPrincipals(identifier))
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_GeneratedDependent(property.Name));
}
outputIdentifiers.Add(identifier, property.Name);
// If this property maps an identifier (in the update pipeline) it may
// also be a store key. If so, the pattern had better be "Identity"
// since otherwise we're dealing with a mutable key.
if (genPattern != StoreGeneratedPattern.Identity &&
processor.IsKeyProperty(propertyOrdinal))
{
throw EntityUtil.NotSupported(System.Data.Entity.Strings.Update_NotSupportedComputedKeyColumn(
EdmProviderManifest.StoreGeneratedPatternFacetName,
XmlConstants.Computed,
XmlConstants.Identity,
property.Name,
property.DeclaringType.FullName));
}
}
}
if (PropagatorFlags.NoFlags != (flags & (omitMask)))
{
// column value matches "omit" pattern, therefore should not be set
omitFromSetList = true;
}
else if (isServerGen)
{
// column value does not match "omit" pattern, but it is server generated
// so it cannot be set
omitFromSetList = true;
// if the row has a modified value overridden by server gen,
// it must still be touched in order to retrieve the value
rowMustBeTouched = true;
}
// make the user is not updating an identity value
if (!omitFromSetList && !insertMode && genPattern == StoreGeneratedPattern.Identity)
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_ModifyingIdentityColumn(
XmlConstants.Identity,
property.Name,
property.DeclaringType.FullName));
}
if (!omitFromSetList) { setClauses.Add(property, propertyResult); }
}
// Construct returning projection
if (0 < returningArguments.Count)
{
returning = commandTree.CreateNewRowExpression(returningArguments);
}
else
{
returning = null;
}
// Construct clauses corresponding to the set clauses
List result = new List(setClauses.Count);
foreach (KeyValuePair setClause in setClauses)
{
EdmProperty property = setClause.Key;
result.Add(new DbSetClause(commandTree,
GeneratePropertyExpression(commandTree, setClause.Key),
GenerateValueExpression(commandTree, setClause.Key, setClause.Value)));
}
return result;
}
///
/// Determines predicate used to identify a row in a table.
///
///
/// Columns are included in the list when:
///
/// - They are keys for the table
/// - They are concurrency values
///
///
/// Command tree hosting the predicate
/// Values for the row being located.
/// Values being updated (may be null).
/// Context for the table containing the row.
/// Output parameter indicating whether a row must be touched
/// (whether it's being modified or not) because it contains a concurrency value
/// Column/value pairs.
private DbExpression BuildPredicate(DbModificationCommandTree commandTree, PropagatorResult referenceRow, PropagatorResult current,
TableChangeProcessor processor, ref bool rowMustBeTouched)
{
Dictionary whereClauses = new Dictionary();
// add all concurrency tokens (note that keys are always concurrency tokens as well)
int propertyOrdinal = 0;
foreach (EdmProperty member in processor.Table.ElementType.Members)
{
// members and result values are ordinally aligned
PropagatorResult expectedValue = referenceRow.GetMemberValue(propertyOrdinal);
PropagatorResult newValue = null == current ? null : current.GetMemberValue(propertyOrdinal);
// check if the rowMustBeTouched value should be set to true (if it isn't already
// true and we've come across a concurrency value)
if (!rowMustBeTouched &&
(HasFlag(expectedValue, PropagatorFlags.ConcurrencyValue) ||
HasFlag(newValue, PropagatorFlags.ConcurrencyValue)))
{
rowMustBeTouched = true;
}
// determine if this is a concurrency value
if (!whereClauses.ContainsKey(member) && // don't add to the set clause twice
(HasFlag(expectedValue, PropagatorFlags.ConcurrencyValue | PropagatorFlags.Key) ||
HasFlag(newValue, PropagatorFlags.ConcurrencyValue | PropagatorFlags.Key))) // tagged as concurrency value
{
whereClauses.Add(member, expectedValue);
}
propertyOrdinal++;
}
// Build a binary AND expression tree from the clauses
DbExpression predicate = null;
foreach (KeyValuePair clause in whereClauses)
{
DbExpression clauseExpression = GenerateEqualityExpression(commandTree, clause.Key, clause.Value);
if (null == predicate) { predicate = clauseExpression; }
else { predicate = commandTree.CreateAndExpression(predicate, clauseExpression); }
}
Debug.Assert(null != predicate, "some predicate term must exist");
return predicate;
}
// Effects: given a "clause" in the form of a property/value pair, produces an equality expression. If the
// value is null, creates an IsNull expression
// Requires: all arguments are set
private DbExpression GenerateEqualityExpression(DbModificationCommandTree commandTree, EdmProperty property, PropagatorResult value)
{
Debug.Assert(null != commandTree && null != property && null != value);
DbExpression propertyExpression = GeneratePropertyExpression(commandTree, property);
if (value.IsNull)
{
return commandTree.CreateIsNullExpression(propertyExpression);
}
if (!TypeSemantics.IsEqualComparable(property.TypeUsage))
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_NonEquatableColumnTypeInClause(
property.Name, property.DeclaringType.Name));
}
return commandTree.CreateEqualsExpression(propertyExpression, GenerateValueExpression(commandTree, property, value));
}
// Effects: given a property, produces a property expression
// Requires: all arguments are set
private static DbExpression GeneratePropertyExpression(DbModificationCommandTree commandTree, EdmProperty property)
{
Debug.Assert(null != commandTree && null != property);
return commandTree.CreatePropertyExpression(property, commandTree.Target.Variable);
}
// Effects: given a propagator result, produces a constant expression describing that value.
// Requires: all arguments are set, and the value must be simple (scalar)
private DbExpression GenerateValueExpression(DbCommandTree commandTree, EdmProperty property, PropagatorResult value)
{
Debug.Assert(null != commandTree && null != value && value.IsSimple && null != property);
if (value.IsNull)
{
return commandTree.CreateNullExpression(Helper.GetModelTypeUsage(property));
}
object principalValue = m_translator.KeyManager.GetPrincipalValue(value);
return commandTree.CreateConstantExpression(principalValue, Helper.GetModelTypeUsage(property));
}
// Effects: returns true iff. the input propagator result has some flag defined in "flags"
// Requires: input is set
private static bool HasFlag(PropagatorResult input, PropagatorFlags flags)
{
if (null == input) { return false; }
return (PropagatorFlags.NoFlags != (flags & input.PropagatorFlags));
}
// Effects: initializes the target (table being modified) for the given DML command tree according
// to the table managed by the processor.
// Requires: all arguments set
private static void SetTarget(TableChangeProcessor processor, DbModificationCommandTree commandTree)
{
Debug.Assert(null != processor && null != commandTree);
// use a fixed var name since the command trees all have exactly one binding
commandTree.Target = commandTree.CreateExpressionBinding(
commandTree.CreateScanExpression(processor.Table), s_targetVarName);
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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