/// <summary>
/// Creates a subquery based on this SelectExpression and makes that table the single entry in
/// <see cref="Tables" />. Clears all other top-level aspects of this SelectExpression.
/// </summary>
/// <returns>
/// A SelectExpression.
/// </returns>
public virtual SelectExpression PushDownSubquery()
{
_subqueryDepth++;
var subquery = new SelectExpression(_querySqlGeneratorFactory, _queryCompilationContext, SystemAliasPrefix);
var columnAliasCounter = 0;
foreach (var expression in _projection)
{
var aliasExpression = expression as AliasExpression;
if (aliasExpression != null)
{
var columnExpression = aliasExpression.TryGetColumnExpression();
if (columnExpression != null &&
subquery._projection.OfType <AliasExpression>()
.Any(ae => (ae.Alias ?? ae.TryGetColumnExpression()?.Name) == (aliasExpression.Alias ?? columnExpression.Name)))
{
aliasExpression.Alias = "c" + columnAliasCounter++;
}
}
else
{
aliasExpression = new AliasExpression("c" + columnAliasCounter++, expression);
}
subquery._projection.Add(aliasExpression);
}
subquery.AddTables(_tables);
subquery.AddToOrderBy(_orderBy);
subquery.Predicate = Predicate;
subquery._limit = _limit;
subquery._offset = _offset;
subquery._isDistinct = _isDistinct;
subquery._subqueryDepth = _subqueryDepth;
subquery.ProjectStarAlias = ProjectStarAlias;
subquery.IsProjectStar = IsProjectStar || !subquery._projection.Any();
_limit = null;
_offset = null;
_isDistinct = false;
ProjectStarAlias = null;
Predicate = null;
ClearTables();
ClearProjection();
ClearOrderBy();
AddTable(subquery, createUniqueAlias: false);
ProjectStarAlias = subquery.Alias;
return(subquery);
}
/// <summary>
/// Creates a new instance of a ColumnReferenceExpression.
/// </summary>
/// <param name="aliasExpression"> The referenced AliasExpression. </param>
/// <param name="tableExpression"> The target table expression. </param>
public ColumnReferenceExpression(
[NotNull] AliasExpression aliasExpression,
[NotNull] TableExpressionBase tableExpression)
: this(
Check.NotNull(aliasExpression, nameof(aliasExpression)).Alias,
aliasExpression,
Check.NotNull(tableExpression, nameof(tableExpression)))
{
}
public InExpression(
[NotNull] AliasExpression operand,
[NotNull] SelectExpression subQuery)
{
Check.NotNull(operand, nameof(operand));
Check.NotNull(subQuery, nameof(subQuery));
Operand = operand;
SubQuery = subQuery;
}
public InExpression(
[NotNull] AliasExpression operand,
[NotNull] IReadOnlyList <Expression> values)
{
Check.NotNull(operand, nameof(operand));
Check.NotNull(values, nameof(values));
Operand = operand;
Values = values;
}
// TODO: Make polymorphic
public virtual Expression UpdateColumnExpression(
[NotNull] Expression expression,
[NotNull] TableExpressionBase tableExpression)
{
Check.NotNull(expression, nameof(expression));
Check.NotNull(tableExpression, nameof(tableExpression));
var columnExpression = expression as ColumnExpression;
if (columnExpression != null)
{
return(new ColumnExpression(columnExpression.Name, columnExpression.Property, tableExpression));
}
var aliasExpression = expression as AliasExpression;
if (aliasExpression != null)
{
var newAliasExpression
= new AliasExpression(
aliasExpression.Alias,
UpdateColumnExpression(aliasExpression.Expression, tableExpression))
{
SourceMember = aliasExpression.SourceMember
};
return(newAliasExpression);
}
switch (expression.NodeType)
{
case ExpressionType.Coalesce:
{
var binaryExpression = (BinaryExpression)expression;
var left = UpdateColumnExpression(binaryExpression.Left, tableExpression);
var right = UpdateColumnExpression(binaryExpression.Right, tableExpression);
return(binaryExpression.Update(left, binaryExpression.Conversion, right));
}
case ExpressionType.Conditional:
{
var conditionalExpression = (ConditionalExpression)expression;
var test = UpdateColumnExpression(conditionalExpression.Test, tableExpression);
var ifTrue = UpdateColumnExpression(conditionalExpression.IfTrue, tableExpression);
var ifFalse = UpdateColumnExpression(conditionalExpression.IfFalse, tableExpression);
return(conditionalExpression.Update(test, ifTrue, ifFalse));
}
}
return(expression);
}
/// <summary>
/// Adds a column to the ORDER BY of this SelectExpression.
/// </summary>
/// <param name="column"> The column name. </param>
/// <param name="property"> The corresponding EF property. </param>
/// <param name="table"> The target table. </param>
/// <param name="orderingDirection"> The ordering direction. </param>
/// <returns>
/// An AliasExpression corresponding to the expression added to the ORDER BY.
/// </returns>
public virtual AliasExpression AddToOrderBy(
[NotNull] string column,
[NotNull] IProperty property,
[NotNull] TableExpressionBase table,
OrderingDirection orderingDirection)
{
Check.NotEmpty(column, nameof(column));
Check.NotNull(property, nameof(property));
Check.NotNull(table, nameof(table));
var columnExpression = new ColumnExpression(column, property, table);
var aliasExpression = new AliasExpression(columnExpression);
if (_orderBy.FindIndex(o => o.Expression.TryGetColumnExpression()?.Equals(columnExpression) ?? false) == -1)
{
_orderBy.Add(new Ordering(aliasExpression, orderingDirection));
}
return(aliasExpression);
}
/// <summary>
/// Adds a ColumnExpression to the projection.
/// </summary>
/// <param name="columnExpression"> The column expression. </param>
/// <returns>
/// The corresponding index of the added expression in <see cref="Projection"/>.
/// </returns>
public virtual int AddToProjection([NotNull] ColumnExpression columnExpression)
{
Check.NotNull(columnExpression, nameof(columnExpression));
var projectionIndex
= _projection
.FindIndex(e =>
{
var ce = e.TryGetColumnExpression();
return(ce != null &&
ce.Property == columnExpression.Property &&
ce.Name == columnExpression.Name &&
ce.TableAlias == columnExpression.TableAlias);
});
if (projectionIndex == -1)
{
var aliasExpression = new AliasExpression(columnExpression);
// Alias != null means SelectExpression in subquery which needs projections to have unique aliases
if (Alias != null)
{
var currentAlias = columnExpression.Name;
var uniqueAlias = CreateUniqueProjectionAlias(currentAlias);
if (!string.Equals(currentAlias, uniqueAlias, StringComparison.OrdinalIgnoreCase))
{
aliasExpression.Alias = uniqueAlias;
}
}
projectionIndex = _projection.Count;
_projection.Add(aliasExpression);
IsProjectStar = false;
}
return(projectionIndex);
}
/// <summary>
/// Adds multiple expressions to the ORDER BY of this SelectExpression.
/// </summary>
/// <param name="orderings"> The orderings expressions. </param>
public virtual void AddToOrderBy([NotNull] IEnumerable <Ordering> orderings)
{
Check.NotNull(orderings, nameof(orderings));
foreach (var ordering in orderings)
{
var aliasExpression = ordering.Expression as AliasExpression;
var columnExpression = ordering.Expression as ColumnExpression;
if (aliasExpression != null)
{
var newAlias = new AliasExpression(aliasExpression.Alias, aliasExpression.Expression);
_orderBy.Add(new Ordering(newAlias, ordering.OrderingDirection));
}
else if (columnExpression != null)
{
_orderBy.Add(new Ordering(new AliasExpression(columnExpression), ordering.OrderingDirection));
}
else
{
_orderBy.Add(ordering);
}
}
}
/// <summary>
/// Adds an <see cref="AliasExpression" /> to the projection.
/// </summary>
/// <param name="aliasExpression"> The alias expression. </param>
/// <returns>
/// The corresponding index of the added expression in <see cref="Projection" />.
/// </returns>
public virtual int AddToProjection([NotNull] AliasExpression aliasExpression)
{
Check.NotNull(aliasExpression, nameof(aliasExpression));
var alias = aliasExpression.Alias;
var expression = aliasExpression.Expression;
var columnExpression = expression as ColumnExpression;
var projectionIndex
= _projection
.FindIndex(e =>
{
var ae = e as AliasExpression;
var ce = e.TryGetColumnExpression();
return((ce != null &&
columnExpression != null &&
ce.Name == columnExpression.Name &&
ce.TableAlias == columnExpression.TableAlias) ||
ae?.Expression == expression);
});
if (projectionIndex == -1)
{
// Alias != null means SelectExpression in subquery which needs projections to have unique aliases
if (Alias != null)
{
var currentAlias = alias ?? columnExpression?.Name ?? expression.NodeType.ToString();
var uniqueAlias = CreateUniqueProjectionAlias(currentAlias);
if (columnExpression == null ||
!string.Equals(currentAlias, uniqueAlias, StringComparison.OrdinalIgnoreCase))
{
alias = uniqueAlias;
}
}
projectionIndex = _projection.Count;
if (alias != null)
{
foreach (var orderByAliasExpression
in _orderBy.Select(o => o.Expression).OfType <AliasExpression>())
{
if (orderByAliasExpression.TryGetColumnExpression() == null)
{
// TODO: This seems bad
if (orderByAliasExpression.Expression.ToString() == expression.ToString())
{
orderByAliasExpression.Alias = alias;
orderByAliasExpression.IsProjected = true;
}
}
}
}
_projection.Add(new AliasExpression(alias, expression));
IsProjectStar = false;
}
return(projectionIndex);
}
// TODO: Make polymorphic
public virtual Expression UpdateColumnExpression(
[NotNull] Expression expression,
[NotNull] TableExpressionBase tableExpression)
{
Check.NotNull(expression, nameof(expression));
Check.NotNull(tableExpression, nameof(tableExpression));
var columnExpression = expression as ColumnExpression;
if (columnExpression != null)
{
return new ColumnExpression(columnExpression.Name, columnExpression.Property, tableExpression);
}
var aliasExpression = expression as AliasExpression;
if (aliasExpression != null)
{
var newAliasExpression
= new AliasExpression(
aliasExpression.Alias,
UpdateColumnExpression(aliasExpression.Expression, tableExpression))
{
SourceMember = aliasExpression.SourceMember
};
return newAliasExpression;
}
switch (expression.NodeType)
{
case ExpressionType.Coalesce:
{
var binaryExpression = (BinaryExpression)expression;
var left = UpdateColumnExpression(binaryExpression.Left, tableExpression);
var right = UpdateColumnExpression(binaryExpression.Right, tableExpression);
return binaryExpression.Update(left, binaryExpression.Conversion, right);
}
case ExpressionType.Conditional:
{
var conditionalExpression = (ConditionalExpression)expression;
var test = UpdateColumnExpression(conditionalExpression.Test, tableExpression);
var ifTrue = UpdateColumnExpression(conditionalExpression.IfTrue, tableExpression);
var ifFalse = UpdateColumnExpression(conditionalExpression.IfFalse, tableExpression);
return conditionalExpression.Update(test, ifTrue, ifFalse);
}
}
return expression;
}
private bool Equals(AliasExpression other) => string.Equals(_alias, other._alias) && Equals(_expression, other._expression);
/// <summary> /// Adds an <see cref="AliasExpression"/> to the projection. /// </summary> /// <param name="aliasExpression"> The alias expression. </param> /// <returns> /// The corresponding index of the added expression in <see cref="Projection"/>. /// </returns> public virtual int AddToProjection([NotNull] AliasExpression aliasExpression) => AddAliasToProjection(aliasExpression.Alias, aliasExpression.Expression);
public virtual SelectExpression PushDownSubquery()
{
_subqueryDepth++;
var subquery = new SelectExpression(_querySqlGeneratorFactory, _queryCompilationContext, SystemAliasPrefix);
var columnAliasCounter = 0;
foreach (var expression in _projection)
{
var aliasExpression = expression as AliasExpression;
if (aliasExpression != null)
{
var columnExpression = aliasExpression.TryGetColumnExpression();
if (columnExpression != null
&& subquery._projection.OfType<AliasExpression>()
.Any(ae => ae.TryGetColumnExpression()?.Name == columnExpression.Name))
{
aliasExpression.Alias = "c" + columnAliasCounter++;
}
}
else
{
aliasExpression = new AliasExpression("c" + columnAliasCounter++, expression);
}
subquery._projection.Add(aliasExpression);
}
subquery.AddTables(_tables);
subquery.AddToOrderBy(_orderBy);
subquery.Predicate = Predicate;
subquery._limit = _limit;
subquery._offset = _offset;
subquery._isDistinct = _isDistinct;
subquery._subqueryDepth = _subqueryDepth;
subquery.IsProjectStar = IsProjectStar || !subquery._projection.Any();
_limit = null;
_offset = null;
_isDistinct = false;
Predicate = null;
ClearTables();
ClearProjection();
ClearOrderBy();
AddTable(subquery, createUniqueAlias: false);
return subquery;
}
private Expression VisitSelectExpression(SelectExpression selectExpression)
{
base.Visit(selectExpression);
if (!RequiresRowNumberPaging(selectExpression))
{
return selectExpression;
}
var subQuery = selectExpression.PushDownSubquery();
foreach (var projection in subQuery.Projection)
{
var alias = projection as AliasExpression;
var column = projection as ColumnExpression;
if (column != null)
{
column = new ColumnExpression(column.Name, column.Property, subQuery);
selectExpression.AddToProjection(column);
continue;
}
column = alias?.TryGetColumnExpression();
if (column != null)
{
column = new ColumnExpression(alias.Alias ?? column.Name, column.Property, subQuery);
alias = new AliasExpression(alias.Alias, column);
selectExpression.AddToProjection(alias);
}
else
{
column = new ColumnExpression(alias?.Alias, alias.Expression.Type, subQuery);
selectExpression.AddToProjection(column);
}
}
if (subQuery.OrderBy.Count == 0)
{
subQuery.AddToOrderBy(
new Ordering(new SqlFunctionExpression("@@RowCount", typeof(int)), OrderingDirection.Asc));
}
var columnExpression = new ColumnExpression(RowNumberColumnName, typeof(int), subQuery);
var rowNumber = new RowNumberExpression(columnExpression, subQuery.OrderBy);
subQuery.ClearOrderBy();
subQuery.AddToProjection(rowNumber, false);
Expression predicate = null;
var offset = subQuery.Offset ?? Expression.Constant(0);
if (subQuery.Offset != null)
{
predicate = Expression.GreaterThan(columnExpression, offset);
}
if (subQuery.Limit != null)
{
var constantValue = (subQuery.Limit as ConstantExpression)?.Value;
var offsetValue = (offset as ConstantExpression)?.Value;
var limitExpression
= constantValue != null
&& offsetValue != null
? (Expression)Expression.Constant((int)offsetValue + (int)constantValue)
: Expression.Add(offset, subQuery.Limit);
var expression = Expression.LessThanOrEqual(columnExpression, limitExpression);
if (predicate != null)
{
expression = Expression.AndAlso(predicate, expression);
}
predicate = expression;
}
selectExpression.Predicate = predicate;
return selectExpression;
}
private bool Equals(AliasExpression other)
=> Equals(_expression, other._expression)
&& string.Equals(_alias, other._alias);
public virtual int AddToProjection([NotNull] ColumnExpression columnExpression)
{
Check.NotNull(columnExpression, nameof(columnExpression));
var projectionIndex
= _projection
.FindIndex(e =>
{
var ce = e.TryGetColumnExpression();
return ce?.Property == columnExpression.Property
&& ce?.Type == columnExpression.Type
&& ce.TableAlias == columnExpression.TableAlias;
});
if (projectionIndex == -1)
{
var aliasExpression = new AliasExpression(columnExpression);
if (Alias != null)
{
var currentAlias = columnExpression.Name;
var uniqueAlias = CreateUniqueProjectionAlias(currentAlias);
if (!string.Equals(currentAlias, uniqueAlias, StringComparison.OrdinalIgnoreCase))
{
aliasExpression.Alias = uniqueAlias;
}
}
projectionIndex = _projection.Count;
_projection.Add(aliasExpression);
IsProjectStar = false;
}
return projectionIndex;
}
public virtual AliasExpression AddToOrderBy(
[NotNull] string column,
[NotNull] IProperty property,
[NotNull] TableExpressionBase table,
OrderingDirection orderingDirection)
{
Check.NotEmpty(column, nameof(column));
Check.NotNull(property, nameof(property));
Check.NotNull(table, nameof(table));
var columnExpression = new ColumnExpression(column, property, table);
var aliasExpression = new AliasExpression(columnExpression);
if (_orderBy.FindIndex(o => o.Expression.TryGetColumnExpression()?.Equals(columnExpression) ?? false) == -1)
{
_orderBy.Add(new Ordering(aliasExpression, orderingDirection));
}
return aliasExpression;
}
/// <summary>
/// Creates a subquery based on this SelectExpression and makes that table the single entry in
/// <see cref="Tables" />. Clears all other top-level aspects of this SelectExpression.
/// </summary>
/// <returns>
/// A SelectExpression.
/// </returns>
public virtual SelectExpression PushDownSubquery()
{
_subqueryDepth++;
var subquery = new SelectExpression(Dependencies, _queryCompilationContext, SystemAliasPrefix);
var columnAliasCounter = 0;
foreach (var expression in _projection)
{
var aliasExpression = expression as AliasExpression;
if (aliasExpression != null)
{
var columnExpression = aliasExpression.TryGetColumnExpression();
if ((columnExpression != null &&
subquery._projection.OfType <AliasExpression>()
.Any(ae => (ae.Alias ?? ae.TryGetColumnExpression()?.Name) == (aliasExpression.Alias ?? columnExpression.Name))) ||
columnExpression == null)
{
aliasExpression.Alias = "c" + columnAliasCounter++;
}
}
else
{
aliasExpression = new AliasExpression("c" + columnAliasCounter++, expression);
}
subquery._projection.Add(aliasExpression);
}
subquery.AddTables(_tables);
subquery.AddToOrderBy(_orderBy);
subquery.Predicate = Predicate;
subquery._limit = _limit;
subquery._offset = _offset;
subquery._isDistinct = _isDistinct;
subquery._subqueryDepth = _subqueryDepth;
subquery.ProjectStarTable = ProjectStarTable;
subquery.IsProjectStar = IsProjectStar || !subquery._projection.Any();
_limit = null;
_offset = null;
_isDistinct = false;
ProjectStarTable = null;
Predicate = null;
ClearTables();
ClearProjection();
ClearOrderBy();
_tables.Add(subquery);
ProjectStarTable = subquery;
foreach (var ordering in subquery.OrderBy)
{
var expression = ordering.Expression;
var aliasExpression = expression as AliasExpression;
if (aliasExpression != null)
{
if (aliasExpression.Alias != null)
{
_orderBy.Add(
new Ordering(
new ColumnExpression(aliasExpression.Alias, aliasExpression.Type, subquery),
ordering.OrderingDirection));
}
else
{
var newExpression = UpdateColumnExpression(aliasExpression.Expression, subquery);
_orderBy.Add(
new Ordering(
new AliasExpression(newExpression), ordering.OrderingDirection));
}
}
else
{
if (!subquery.IsProjectStar)
{
subquery.AddToProjection(expression);
}
var newExpression = UpdateColumnExpression(expression, subquery);
_orderBy.Add(
new Ordering(
new AliasExpression(newExpression), ordering.OrderingDirection));
}
}
if (subquery.Limit == null &&
subquery.Offset == null)
{
subquery.ClearOrderBy();
}
return(subquery);
}
public virtual void AddToOrderBy([NotNull] IEnumerable<Ordering> orderings)
{
Check.NotNull(orderings, nameof(orderings));
foreach (var ordering in orderings)
{
var aliasExpression = ordering.Expression as AliasExpression;
var columnExpression = ordering.Expression as ColumnExpression;
if (aliasExpression != null)
{
var newAlias = new AliasExpression(aliasExpression.Alias, aliasExpression.Expression);
_orderBy.Add(new Ordering(newAlias, ordering.OrderingDirection));
}
else if (columnExpression != null)
{
_orderBy.Add(new Ordering(new AliasExpression(columnExpression), ordering.OrderingDirection));
}
else
{
_orderBy.Add(ordering);
}
}
}