internal static string GenerateUpdateSql(DbUpdateCommandTree tree, out List<DbParameter> parameters)
{
StringBuilder commandText = new StringBuilder(CommandTextBuilderInitialCapacity);
ExpressionTranslator translator = new ExpressionTranslator(commandText, tree, null != tree.Returning);
bool first = true;
commandText.Append("UPDATE ");
tree.Target.Expression.Accept(translator);
commandText.AppendLine();
// set c1 = ..., c2 = ..., ...
commandText.Append("SET ");
foreach (DbSetClause setClause in tree.SetClauses)
{
if (first)
{
first = false;
}
else
{
commandText.Append(", ");
}
setClause.Property.Accept(translator);
commandText.Append(" = ");
setClause.Value.Accept(translator);
translator.RegisterMemberValue(setClause.Property, setClause.Value);
}
if (first)
{
// If first is still true, it indicates there were no set
// clauses. Introduce a fake set clause so that:
// - we acquire the appropriate locks
// - server-gen columns (e.g. timestamp) get recomputed
EntitySetBase table = ((DbScanExpression)tree.Target.Expression).Target;
// hope this column isn't indexed to not waste power
EdmMember someColumn = table.ElementType.Members.Last(x => !IsStoreGenerated(x));
commandText.AppendFormat("{0} = {0}", GenerateMemberSql(someColumn));
}
commandText.AppendLine();
// where c1 = ..., c2 = ...
commandText.Append("WHERE ");
tree.Predicate.Accept(translator);
commandText.AppendLine();
// generate returning sql
GenerateReturningSql(commandText, tree, translator, tree.Returning);
parameters = translator.Parameters;
return commandText.ToString();
}
internal static string GenerateUpdateSql(DbUpdateCommandTree tree, SqlVersion sqlVersion, out List<SqlParameter> parameters)
{
const string dummySetParameter = "@p";
StringBuilder commandText = new StringBuilder(s_commandTextBuilderInitialCapacity);
ExpressionTranslator translator = new ExpressionTranslator(commandText, tree, null != tree.Returning, sqlVersion);
if (tree.SetClauses.Count == 0)
{
commandText.AppendLine("declare " + dummySetParameter + " int");
}
// update [schemaName].[tableName]
commandText.Append("update ");
tree.Target.Expression.Accept(translator);
commandText.AppendLine();
// set c1 = ..., c2 = ..., ...
bool first = true;
commandText.Append("set ");
foreach (DbSetClause setClause in tree.SetClauses)
{
if (first) { first = false; }
else { commandText.Append(", "); }
setClause.Property.Accept(translator);
commandText.Append(" = ");
setClause.Value.Accept(translator);
}
if (first)
{
// If first is still true, it indicates there were no set
// clauses. Introduce a fake set clause so that:
// - we acquire the appropriate locks
// - server-gen columns (e.g. timestamp) get recomputed
//
// We use the following pattern:
//
// update Foo
// set @p = 0
// where ...
commandText.Append(dummySetParameter + " = 0");
}
commandText.AppendLine();
// where c1 = ..., c2 = ...
commandText.Append("where ");
tree.Predicate.Accept(translator);
commandText.AppendLine();
// generate returning sql
GenerateReturningSql(commandText, tree, null, translator, tree.Returning, false);
parameters = translator.Parameters;
return commandText.ToString();
}
internal static string GenerateUpdateSql(DbUpdateCommandTree tree, out List<DbParameter> parameters)
{
StringBuilder commandText = new StringBuilder(s_commandTextBuilderInitialCapacity);
ExpressionTranslator translator = new ExpressionTranslator(commandText, tree, null != tree.Returning);
// update [schemaName].[tableName]
commandText.Append("update ");
tree.Target.Expression.Accept(translator);
commandText.AppendLine();
// set c1 = ..., c2 = ..., ...
bool first = true;
commandText.Append("set ");
foreach (DbSetClause setClause in tree.SetClauses)
{
if (first) { first = false; }
else { commandText.Append(", "); }
setClause.Property.Accept(translator);
commandText.Append(" = ");
setClause.Value.Accept(translator);
}
if (first)
{
// If first is still true, it indicates there were no set
// clauses. Introduce a fake set clause so that:
// - we acquire the appropriate locks
// - server-gen columns (e.g. timestamp) get recomputed
//
// We use the following pattern:
//
// update SomeTable
// set @i = 0
// where ...
DbParameter parameter =
translator.CreateParameter(
default(Int32),
TypeUsage.CreateDefaultTypeUsage(PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.Int32)));
commandText.Append(parameter.ParameterName);
commandText.Append(" = 0");
}
commandText.AppendLine();
// where c1 = ..., c2 = ...
commandText.Append("where ");
tree.Predicate.Accept(translator);
commandText.AppendLine();
// generate returning sql
GenerateReturningSql(commandText, tree, translator, tree.Returning);
parameters = translator.Parameters;
return commandText.ToString();
}
protected virtual void VisitUpdateCommandTree(DbUpdateCommandTree updateTree)
{
EntityUtil.CheckArgumentNull(updateTree, "updateTree");
this.VisitExpressionBindingPre(updateTree.Target);
this.VisitModificationClauses(updateTree.SetClauses);
this.VisitExpression(updateTree.Predicate);
if (updateTree.Returning != null)
{
this.VisitExpression(updateTree.Returning);
}
this.VisitExpressionBindingPost(updateTree.Target);
}
/// <summary>
/// This method is added as a part of the fix for bug 13533
/// In this method we try to see from the command tree whether there is any
/// updatable column(Property) available on the table(EntityType)
private static bool GetUpdatableColumn(DbUpdateCommandTree tree, out string updatableColumnName)
{
var result = false;
updatableColumnName = "";
var entityType = (EntityType)tree.Target.VariableType.EdmType;
foreach (var edmProperty in entityType.Properties)
{
if (entityType.KeyMembers.Contains(edmProperty.Name))
{
// continue if it is a primary key
continue;
}
if (rowversionString == edmProperty.TypeUsage.EdmType.Name)
{
// if the property is of type rowversion then we continue checking the next item in the list
continue;
}
// check whether the property is a identity type
if (edmProperty.TypeUsage.Facets.Contains(storeGeneratedPatternString))
{
var fct = edmProperty.TypeUsage.Facets.GetValue(storeGeneratedPatternString, false);
if (StoreGeneratedPattern.Identity
== (StoreGeneratedPattern)fct.Value)
{
// continue to check for the next property if the current property is a identity
continue;
}
}
//if the column is found then return the column name string
updatableColumnName = edmProperty.Name;
result = true;
break;
}
return result;
}
internal static string[] GenerateUpdateSql(DbUpdateCommandTree tree, out List<DbParameter> parameters, bool isLocalProvider)
{
var commandTexts = new List<String>();
var commandText = new StringBuilder(s_commandTextBuilderInitialCapacity);
var translator = new ExpressionTranslator(commandText, tree, null != tree.Returning, isLocalProvider);
// update [schemaName].[tableName]
commandText.Append("update ");
tree.Target.Expression.Accept(translator);
commandText.AppendLine();
// set c1 = ..., c2 = ..., ...
var first = true;
commandText.Append("set ");
foreach (DbSetClause setClause in tree.SetClauses)
{
if (first)
{
first = false;
}
else
{
commandText.Append(", ");
}
setClause.Property.Accept(translator);
commandText.Append(" = ");
setClause.Value.Accept(translator);
}
if (first)
{
// If first is still true, it indicates there were no set
// clauses.
// - we acquire the appropriate locks
// - server-gen columns (e.g. timestamp) get recomputed
//
// Bug fix #13533 : A fake update DML updating some column item
// with the same value as before to acquire the lock on the table
// while updating some columns in another table. This happens when
// both the table are dependent on an entity and the members of entity
// which is mapped to one table is being updated and the other table
// needs to be locked for consistancy.
string updatableColumnName;
if (GetUpdatableColumn(tree, out updatableColumnName))
{
commandText.Append("[");
commandText.Append(CommonUtils.EscapeSquareBraceNames(updatableColumnName));
commandText.Append("] ");
commandText.Append(" = ");
commandText.Append("[");
commandText.Append(CommonUtils.EscapeSquareBraceNames(updatableColumnName));
commandText.Append("] ");
}
else
{
// Throw some meaningful error
throw ADP1.Update(
EntityRes.GetString(EntityRes.UpdateStatementCannotBeGeneratedForAcquiringLock),
null);
}
}
commandText.AppendLine();
// where c1 = ..., c2 = ...
commandText.Append("where ");
tree.Predicate.Accept(translator);
commandText.AppendLine();
commandTexts.Add(commandText.ToString());
commandText.Length = 0;
// generate returning sql
GenerateReturningSql(commandText, tree, translator, tree.Returning);
if (!String.IsNullOrEmpty(commandText.ToString()))
{
commandTexts.Add(commandText.ToString());
}
parameters = translator.Parameters;
return commandTexts.ToArray();
}
public SqlUpdateGenerator(DbUpdateCommandTree commandTree)
{
_commandTree = commandTree;
}
protected virtual void VisitUpdateCommandTree(DbUpdateCommandTree updateTree)
{
EntityUtil.CheckArgumentNull(updateTree, "updateTree");
this.VisitExpressionBindingPre(updateTree.Target);
this.VisitModificationClauses(updateTree.SetClauses);
this.VisitExpression(updateTree.Predicate);
if (updateTree.Returning != null)
{
this.VisitExpression(updateTree.Returning);
}
this.VisitExpressionBindingPost(updateTree.Target);
}
private DbModificationCommandTree RebuildCommandTree(DbModificationCommandTree originalTree, Dictionary<DbSetClause, DbSetClause> 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;
}
/// <summary>
/// Builds an update command.
/// </summary>
/// <param name="oldRow">Old value of the row being updated.</param>
/// <param name="newRow">New value for the row being updated.</param>
/// <param name="processor">Context for the table containing row.</param>
/// <returns>Update command.</returns>
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;
DbExpressionBinding target = GetTarget(processor);
// Create set clauses and returning parameter
Dictionary<int, string> outputIdentifiers;
DbExpression returning;
List<DbModificationClause> setClauses = new List<DbModificationClause>();
foreach (DbModificationClause clause in BuildSetClauses(
target, newRow, oldRow, processor, /* insertMode */ false, out outputIdentifiers, out returning,
ref rowMustBeTouched))
{
setClauses.Add(clause);
}
// Construct predicate identifying the row to modify
DbExpression predicate = BuildPredicate(target, oldRow, newRow, processor, ref rowMustBeTouched);
if (0 == setClauses.Count)
{
if (rowMustBeTouched)
{
List<IEntityStateEntry> stateEntries = new List<IEntityStateEntry>();
stateEntries.AddRange(SourceInterpreter.GetAllStateEntries(
oldRow, m_translator, processor.Table));
stateEntries.AddRange(SourceInterpreter.GetAllStateEntries(
newRow, m_translator, processor.Table));
if (stateEntries.All(it => (it.State == EntityState.Unchanged)))
{
rowMustBeTouched = false;
}
}
// Determine if there is nothing to do (i.e., no values to set,
// no computed columns, and no concurrency validation required)
if (!rowMustBeTouched)
{
return null;
}
}
// Initialize DML command tree
DbUpdateCommandTree commandTree =
new DbUpdateCommandTree(m_translator.MetadataWorkspace, DataSpace.SSpace, target, predicate, setClauses.AsReadOnly(), returning);
// Create command
UpdateCommand command = new DynamicUpdateCommand(processor, m_translator, ModificationOperator.Update, oldRow, newRow, commandTree, outputIdentifiers);
return command;
}
protected virtual void VisitUpdateCommandTree(DbUpdateCommandTree updateTree)
{
//Contract.Requires(updateTree != null);
VisitExpressionBindingPre(updateTree.Target);
VisitModificationClauses(updateTree.SetClauses);
VisitExpression(updateTree.Predicate);
if (updateTree.Returning != null)
{
VisitExpression(updateTree.Returning);
}
VisitExpressionBindingPost(updateTree.Target);
}
