/// <summary>
/// Determines column/value used to set values for a row.
/// </summary>
/// <remarks>
/// The following columns are not included in the result:
/// <list>
/// <item>Keys in non-insert operations (keys are only set for inserts).</item>
/// <item>Values flagged 'preserve' (these are values the propagator claims are untouched).</item>
/// <item>Server generated values.</item>
/// </list>
/// </remarks>
/// <param name="target">Expression binding representing the table.</param>
/// <param name="row">Row containing values to set.</param>
/// <param name="processor">Context for table.</param>
/// <param name="insertMode">Determines whether key columns and 'preserve' columns are
/// omitted from the list.</param>
/// <param name="outputIdentifiers">Dictionary listing server generated identifiers.</param>
/// <param name="returning">DbExpression describing result projection for server generated values.</param>
/// <param name="rowMustBeTouched">Indicates whether the row must be touched
/// because it produces a value (e.g. computed)</param>
/// <returns>Column value pairs.</returns>
private IEnumerable <DbModificationClause> BuildSetClauses(DbExpressionBinding target, PropagatorResult row,
PropagatorResult originalRow, TableChangeProcessor processor, bool insertMode, out Dictionary <int, string> outputIdentifiers, out DbExpression returning,
ref bool rowMustBeTouched)
{
Dictionary <EdmProperty, PropagatorResult> setClauses = new Dictionary <EdmProperty, PropagatorResult>();
List <KeyValuePair <string, DbExpression> > returningArguments = new List <KeyValuePair <string, DbExpression> >();
outputIdentifiers = new Dictionary <int, string>();
// 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 = target.Variable.Property(property);
returningArguments.Add(new KeyValuePair <string, DbExpression>(property.Name, propertyExpression));
// check if this is a server generated identifier
int 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 the error only if the value actually changed
Debug.Assert(originalRow != null, "Updated records should have a original row");
PropagatorResult originalPropertyResult = originalRow.GetMemberValue(propertyOrdinal);
Debug.Assert(originalPropertyResult.IsSimple, "Server Gen property that is not primitive?");
Debug.Assert(propertyResult.IsSimple, "Server Gen property that is not primitive?");
if (!ByValueEqualityComparer.Default.Equals(originalPropertyResult.GetSimpleValue(), propertyResult.GetSimpleValue()))
{
throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.Update_ModifyingIdentityColumn(
XmlConstants.Identity,
property.Name,
property.DeclaringType.FullName));
}
else
{
omitFromSetList = true;
}
}
if (!omitFromSetList)
{
setClauses.Add(property, propertyResult);
}
}
// Construct returning projection
if (0 < returningArguments.Count)
{
returning = DbExpressionBuilder.NewRow(returningArguments);
}
else
{
returning = null;
}
// Construct clauses corresponding to the set clauses
List <DbModificationClause> result = new List <DbModificationClause>(setClauses.Count);
foreach (KeyValuePair <EdmProperty, PropagatorResult> setClause in setClauses)
{
EdmProperty property = setClause.Key;
result.Add(new DbSetClause(
GeneratePropertyExpression(target, setClause.Key),
GenerateValueExpression(setClause.Key, setClause.Value)));
}
return(result);
}