// <summary>
// Write out a SQL select statement as a string.
// We have to
// <list type="number">
// <item>
// Check whether the aliases extents we use in this statement have
// to be renamed.
// We first create a list of all the aliases used by the outer extents.
// For each of the FromExtents( or AllJoinExtents if it is non-null),
// rename it if it collides with the previous list.
// </item>
// <item>Write each of the clauses (if it exists) as a string</item>
// </list>
// </summary>
public void WriteSql(SqlWriter writer, SqlGenerator sqlGenerator)
{
#region Check if FROM aliases need to be renamed
// Create a list of the aliases used by the outer extents
// JoinSymbols have to be treated specially.
List <string> outerExtentAliases = null;
if ((null != outerExtents) &&
(0 < outerExtents.Count))
{
foreach (var outerExtent in outerExtents.Keys)
{
var joinSymbol = outerExtent as JoinSymbol;
if (joinSymbol != null)
{
foreach (var symbol in joinSymbol.FlattenedExtentList)
{
if (null == outerExtentAliases)
{
outerExtentAliases = new List <string>();
}
outerExtentAliases.Add(symbol.NewName);
}
}
else
{
if (null == outerExtentAliases)
{
outerExtentAliases = new List <string>();
}
outerExtentAliases.Add(outerExtent.NewName);
}
}
}
// An then rename each of the FromExtents we have
// If AllJoinExtents is non-null - it has precedence.
// The new name is derived from the old name - we append an increasing int.
var extentList = AllJoinExtents ?? fromExtents;
if (null != extentList)
{
foreach (var fromAlias in extentList)
{
if ((null != outerExtentAliases) &&
outerExtentAliases.Contains(fromAlias.Name))
{
var i = sqlGenerator.AllExtentNames[fromAlias.Name];
string newName;
do
{
++i;
newName = fromAlias.Name + i.ToString(CultureInfo.InvariantCulture);
}while (sqlGenerator.AllExtentNames.ContainsKey(newName));
sqlGenerator.AllExtentNames[fromAlias.Name] = i;
fromAlias.NewName = newName;
// Add extent to list of known names (although i is always incrementing, "prefix11" can
// eventually collide with "prefix1" when it is extended)
sqlGenerator.AllExtentNames[newName] = 0;
}
// Add the current alias to the list, so that the extents
// that follow do not collide with me.
if (null == outerExtentAliases)
{
outerExtentAliases = new List <string>();
}
outerExtentAliases.Add(fromAlias.NewName);
}
}
#endregion
// Increase the indent, so that the Sql statement is nested by one tab.
writer.Indent += 1; // ++ can be confusing in this context
@select.WriteSql(writer, sqlGenerator);
writer.WriteLine();
writer.Write("FROM ");
From.WriteSql(writer, sqlGenerator);
if ((null != @where) &&
!Where.IsEmpty)
{
writer.WriteLine();
writer.Write("WHERE ");
Where.WriteSql(writer, sqlGenerator);
}
if ((null != groupBy) &&
!GroupBy.IsEmpty)
{
writer.WriteLine();
writer.Write("GROUP BY ");
GroupBy.WriteSql(writer, sqlGenerator);
}
if ((null != orderBy) &&
!OrderBy.IsEmpty &&
(IsTopMost || Select.Top != null || Select.Skip != null))
{
writer.WriteLine();
writer.Write("ORDER BY ");
OrderBy.WriteSql(writer, sqlGenerator);
}
if (null != Select.Skip)
{
writer.WriteLine();
WriteOffsetFetch(writer, Select.Top, Select.Skip, sqlGenerator); // Write OFFSET, FETCH clause.
}
--writer.Indent;
}
// This function generates OFFSET, FETCH clause from Top and Skip information.
// Note that this should be used only when Skip is present.
//
private static void WriteOffsetFetch(SqlWriter writer, TopClause top, SkipClause skip, SqlGenerator sqlGenerator)
{
DebugCheck.NotNull(skip);
skip.WriteSql(writer, sqlGenerator);
if (top != null)
{
writer.Write("FETCH NEXT ");
top.TopCount.WriteSql(writer, sqlGenerator);
writer.Write(" ROWS ONLY ");
}
}
// Generates T-SQL describing a member
// Requires: member must belong to an entity type (a safe requirement for DML
// SQL gen, where we only access table columns)
internal static string GenerateMemberTSql(EdmMember member)
{
return(SqlGenerator.QuoteIdentifier(member.Name));
}
internal static string GenerateUpdateSql(
DbUpdateCommandTree tree,
SqlGenerator sqlGenerator,
out List <SqlParameter> parameters,
bool generateReturningSql = true,
bool upperCaseKeywords = true)
{
const string dummySetParameter = "@p";
var commandText
= new SqlStringBuilder(CommandTextBuilderInitialCapacity)
{
UpperCaseKeywords = upperCaseKeywords
};
var translator = new ExpressionTranslator(commandText, tree, null != tree.Returning, sqlGenerator);
if (tree.SetClauses.Count == 0)
{
commandText.AppendKeyword("declare ");
commandText.AppendLine(dummySetParameter + " int");
}
// update [schemaName].[tableName]
commandText.AppendKeyword("update ");
tree.Target.Expression.Accept(translator);
commandText.AppendLine();
// set c1 = ..., c2 = ..., ...
var first = true;
commandText.AppendKeyword("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 @p = 0
// where ...
commandText.Append(dummySetParameter + " = 0");
}
commandText.AppendLine();
// where c1 = ..., c2 = ...
commandText.AppendKeyword("where ");
tree.Predicate.Accept(translator);
commandText.AppendLine();
if (generateReturningSql)
{
GenerateReturningSql(commandText, tree, null, translator, tree.Returning, false);
}
parameters = translator.Parameters;
return(commandText.ToString());
}
internal static string GenerateInsertSql(
DbInsertCommandTree tree,
SqlGenerator sqlGenerator,
out List <SqlParameter> parameters,
bool generateReturningSql = true,
bool upperCaseKeywords = true,
bool createParameters = true)
{
var commandText
= new SqlStringBuilder(CommandTextBuilderInitialCapacity)
{
UpperCaseKeywords = upperCaseKeywords
};
var translator
= new ExpressionTranslator(
commandText,
tree,
null != tree.Returning,
sqlGenerator,
createParameters: createParameters);
var useGeneratedValuesVariable = UseGeneratedValuesVariable(tree, sqlGenerator.SqlVersion);
var tableType = (EntityType)((DbScanExpression)tree.Target.Expression).Target.ElementType;
if (useGeneratedValuesVariable)
{
// manufacture the variable, e.g. "declare @generated_values table(id uniqueidentifier)"
commandText
.AppendKeyword("declare ")
.Append(GeneratedValuesVariableName)
.Append(" table(");
var first = true;
foreach (var column in tableType.KeyMembers)
{
if (first)
{
first = false;
}
else
{
commandText.Append(", ");
}
commandText
.Append(GenerateMemberTSql(column))
.Append(" ")
.Append(GetVariableType(sqlGenerator, column));
Facet collationFacet;
if (column.TypeUsage.Facets.TryGetValue(DbProviderManifest.CollationFacetName, false, out collationFacet))
{
var collation = collationFacet.Value as string;
if (!string.IsNullOrEmpty(collation))
{
commandText.AppendKeyword(" collate ").Append(collation);
}
}
}
Debug.Assert(!first, "if useGeneratedValuesVariable is true, it implies some columns do not have values");
commandText.AppendLine(")");
}
// insert [schemaName].[tableName]
commandText.AppendKeyword("insert ");
tree.Target.Expression.Accept(translator);
if (0 < tree.SetClauses.Count)
{
// (c1, c2, c3, ...)
commandText.Append("(");
var first = true;
foreach (DbSetClause setClause in tree.SetClauses)
{
if (first)
{
first = false;
}
else
{
commandText.Append(", ");
}
setClause.Property.Accept(translator);
}
commandText.AppendLine(")");
}
else
{
commandText.AppendLine();
}
if (useGeneratedValuesVariable)
{
// output inserted.id into @generated_values
commandText.AppendKeyword("output ");
var first = true;
foreach (var column in tableType.KeyMembers)
{
if (first)
{
first = false;
}
else
{
commandText.Append(", ");
}
commandText.Append("inserted.");
commandText.Append(GenerateMemberTSql(column));
}
commandText
.AppendKeyword(" into ")
.AppendLine(GeneratedValuesVariableName);
}
if (0 < tree.SetClauses.Count)
{
// values c1, c2, ...
var first = true;
commandText.AppendKeyword("values (");
foreach (DbSetClause setClause in tree.SetClauses)
{
if (first)
{
first = false;
}
else
{
commandText.Append(", ");
}
setClause.Value.Accept(translator);
translator.RegisterMemberValue(setClause.Property, setClause.Value);
}
commandText.AppendLine(")");
}
else
{
// default values
commandText.AppendKeyword("default values");
commandText.AppendLine();
}
if (generateReturningSql)
{
GenerateReturningSql(commandText, tree, tableType, translator, tree.Returning, useGeneratedValuesVariable);
}
parameters = translator.Parameters;
return(commandText.ToString());
}
public void WriteSql(SqlWriter writer, SqlGenerator sqlGenerator)
{
// Symbol pair should never be part of a SqlBuilder.
Debug.Assert(false);
}
public DmlFunctionSqlGenerator(SqlGenerator sqlGenerator)
{
DebugCheck.NotNull(sqlGenerator);
_sqlGenerator = sqlGenerator;
}