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Generate Unique alias for table names
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@smitpatel
smitpatel committed Feb 17, 2016
1 parent 36f39a6 commit ef15f26
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Showing 24 changed files with 1,069 additions and 926 deletions.
13 changes: 7 additions & 6 deletions ...ityFrameworkCore.Relational/Query/ExpressionVisitors/Internal/IncludeExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -135,7 +135,7 @@ var targetTableExpression

var targetEntityType = navigation.GetTargetType();
var targetTableName = _relationalAnnotationProvider.For(targetEntityType).TableName;
var targetTableAlias = targetTableName[0].ToString().ToLower();
var targetTableAlias = _queryCompilationContext.CreateUniqueTableAlias(targetTableName[0].ToString().ToLower());

if (!navigation.IsCollection())
{
Expand Down Expand Up @@ -179,7 +179,7 @@ var materializer

selectExpression.Predicate = oldPredicate;
selectExpression.RemoveTable(joinExpression);
selectExpression.AddTable(newJoinExpression);
selectExpression.AddTable(newJoinExpression, createUniqueAlias: false);
joinExpression = newJoinExpression;
}

Expand Down Expand Up @@ -223,7 +223,7 @@ var principalTable
OrderingDirection.Asc);
}

var targetSelectExpression = _selectExpressionFactory.Create();
var targetSelectExpression = _selectExpressionFactory.Create(_queryCompilationContext);

targetTableExpression
= new TableExpression(
Expand All @@ -232,7 +232,7 @@ var principalTable
targetTableAlias,
querySource);

targetSelectExpression.AddTable(targetTableExpression);
targetSelectExpression.AddTable(targetTableExpression, createUniqueAlias: false);

var materializer
= _materializerFactory
Expand Down Expand Up @@ -290,8 +290,9 @@ var innerJoinSelectExpression
private JoinExpressionBase AdjustJoinExpression(
SelectExpression selectExpression, JoinExpressionBase joinExpression)
{
var subquery = new SelectExpression(_querySqlGeneratorFactory, joinExpression.Alias);
subquery.AddTable(joinExpression.TableExpression);
var subquery = new SelectExpression(_querySqlGeneratorFactory, _queryCompilationContext) { Alias = joinExpression.Alias };
// Don't create new alias when adding tables to subquery
subquery.AddTable(joinExpression.TableExpression, createUniqueAlias: false);
subquery.IsProjectStar = true;
subquery.Predicate = selectExpression.Predicate;

Expand Down
2 changes: 1 addition & 1 deletion ...orkCore.Relational/Query/ExpressionVisitors/RelationalEntityQueryableExpressionVisitor.cs
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Expand Up @@ -117,7 +117,7 @@ protected override Expression VisitEntityQueryable(Type elementType)
var relationalQueryCompilationContext = QueryModelVisitor.QueryCompilationContext;
var entityType = _model.FindEntityType(elementType);

var selectExpression = _selectExpressionFactory.Create();
var selectExpression = _selectExpressionFactory.Create(relationalQueryCompilationContext);

QueryModelVisitor.AddQuery(_querySource, selectExpression);

Expand Down
4 changes: 2 additions & 2 deletions src/Microsoft.EntityFrameworkCore.Relational/Query/Expressions/ISelectExpressionFactory.cs
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Expand Up @@ -7,8 +7,8 @@ namespace Microsoft.EntityFrameworkCore.Query.Expressions
{
public interface ISelectExpressionFactory
{
SelectExpression Create();
SelectExpression Create([NotNull]RelationalQueryCompilationContext queryCompilationContext);

SelectExpression Create([NotNull] string alias);
SelectExpression Create([NotNull]RelationalQueryCompilationContext queryCompilationContext, [NotNull] string alias);
}
}
82 changes: 37 additions & 45 deletions src/Microsoft.EntityFrameworkCore.Relational/Query/Expressions/SelectExpression.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ public class SelectExpression : TableExpressionBase
#endif

private readonly IQuerySqlGeneratorFactory _querySqlGeneratorFactory;
private readonly RelationalQueryCompilationContext _queryCompilationContext;
private readonly List<Expression> _projection = new List<Expression>();
private readonly List<TableExpressionBase> _tables = new List<TableExpressionBase>();
private readonly List<Ordering> _orderBy = new List<Ordering>();
Expand All @@ -35,22 +36,27 @@ public class SelectExpression : TableExpressionBase

public virtual Expression Predicate { get; [param: CanBeNull] set; }

public SelectExpression([NotNull] IQuerySqlGeneratorFactory querySqlGeneratorFactory)
public SelectExpression([NotNull] IQuerySqlGeneratorFactory querySqlGeneratorFactory,
[NotNull] RelationalQueryCompilationContext queryCompilationContext)
: base(null, null)
{
Check.NotNull(querySqlGeneratorFactory, nameof(querySqlGeneratorFactory));
Check.NotNull(queryCompilationContext, nameof(queryCompilationContext));

_querySqlGeneratorFactory = querySqlGeneratorFactory;
_queryCompilationContext = queryCompilationContext;
}

public SelectExpression(
[NotNull] IQuerySqlGeneratorFactory querySqlGeneratorFactory,
[NotNull] RelationalQueryCompilationContext queryCompilationContext,
[NotNull] string alias)
: base(null, Check.NotNull(alias, nameof(alias)))
: this(querySqlGeneratorFactory, queryCompilationContext)
{
Check.NotNull(querySqlGeneratorFactory, nameof(querySqlGeneratorFactory));
Check.NotNull(alias, nameof(alias));

_querySqlGeneratorFactory = querySqlGeneratorFactory;
// When assigning alias to select expression make it unique
Alias = queryCompilationContext.CreateUniqueTableAlias(alias);
}

public override Type Type => _projection.Count == 1
Expand All @@ -62,7 +68,7 @@ public virtual SelectExpression Clone([NotNull] string alias)
Check.NotNull(alias, nameof(alias));

var selectExpression
= new SelectExpression(_querySqlGeneratorFactory, alias)
= new SelectExpression(_querySqlGeneratorFactory, _queryCompilationContext, alias)
{
_limit = _limit,
_offset = _offset,
Expand All @@ -84,13 +90,32 @@ var selectExpression

public virtual bool IsProjectStar { get; set; }

public virtual void AddTable([NotNull] TableExpressionBase tableExpression)
=> _tables.Add(Check.NotNull(tableExpression, nameof(tableExpression)));
public virtual void AddTable([NotNull] TableExpressionBase tableExpression, bool createUniqueAlias = true)
{
Check.NotNull(tableExpression, nameof(tableExpression));

if (createUniqueAlias)
{
tableExpression.Alias = _queryCompilationContext.CreateUniqueTableAlias(tableExpression.Alias);
}
_tables.Add(tableExpression);
}

public virtual void AddTables([NotNull] IEnumerable<TableExpressionBase> tableExpressions)
=> _tables.AddRange(Check.NotNull(tableExpressions, nameof(tableExpressions)));
{
Check.NotNull(tableExpressions, nameof(tableExpressions));

public virtual void ClearTables() => _tables.Clear();
// Multiple tables are added while moving current select expression inside subquery hence it does not need to generate unique alias
foreach (var tableExpression in tableExpressions.ToList())
{
AddTable(tableExpression, createUniqueAlias: false);
}
}

public virtual void ClearTables()
{
_tables.Clear();
}

public virtual bool IsCorrelated() => new CorrelationFindingExpressionVisitor().IsCorrelated(this);

Expand Down Expand Up @@ -229,7 +254,7 @@ public virtual SelectExpression PushDownSubquery()
{
_subqueryDepth++;

var subquery = new SelectExpression(_querySqlGeneratorFactory, SystemAliasPrefix + _subqueryDepth);
var subquery = new SelectExpression(_querySqlGeneratorFactory, _queryCompilationContext, SystemAliasPrefix);

var columnAliasCounter = 0;

Expand Down Expand Up @@ -277,7 +302,7 @@ public virtual SelectExpression PushDownSubquery()
ClearProjection();
ClearOrderBy();

AddTable(subquery);
AddTable(subquery, createUniqueAlias: false);

return subquery;
}
Expand Down Expand Up @@ -382,7 +407,7 @@ var projectionIndex

if (alias != null)
{
foreach (var orderByAliasExpression
foreach (var orderByAliasExpression
in _orderBy.Select(o => o.Expression).OfType<AliasExpression>())
{
if (orderByAliasExpression.TryGetColumnExpression() == null)
Expand Down Expand Up @@ -625,8 +650,6 @@ public virtual void AddCrossJoin(
Check.NotNull(tableExpression, nameof(tableExpression));
Check.NotNull(projection, nameof(projection));

tableExpression.Alias = CreateUniqueTableAlias(tableExpression.Alias);

_tables.Add(new CrossJoinExpression(tableExpression));
_projection.AddRange(projection);
}
Expand All @@ -638,8 +661,6 @@ public virtual void AddLateralJoin(
Check.NotNull(tableExpression, nameof(tableExpression));
Check.NotNull(projection, nameof(projection));

tableExpression.Alias = CreateUniqueTableAlias(tableExpression.Alias);

_tables.Add(new LateralJoinExpression(tableExpression));
_projection.AddRange(projection);
}
Expand All @@ -658,8 +679,6 @@ public virtual JoinExpressionBase AddInnerJoin(
Check.NotNull(tableExpression, nameof(tableExpression));
Check.NotNull(projection, nameof(projection));

tableExpression.Alias = CreateUniqueTableAlias(tableExpression.Alias);

var innerJoinExpression = new InnerJoinExpression(tableExpression);

_tables.Add(innerJoinExpression);
Expand All @@ -682,8 +701,6 @@ public virtual JoinExpressionBase AddOuterJoin(
Check.NotNull(tableExpression, nameof(tableExpression));
Check.NotNull(projection, nameof(projection));

tableExpression.Alias = CreateUniqueTableAlias(tableExpression.Alias);

var outerJoinExpression = new LeftOuterJoinExpression(tableExpression);

_tables.Add(outerJoinExpression);
Expand All @@ -692,31 +709,6 @@ public virtual JoinExpressionBase AddOuterJoin(
return outerJoinExpression;
}

public virtual string CreateUniqueTableAlias()
=> CreateUniqueTableAlias(SystemAliasPrefix);

private string CreateUniqueTableAlias(string currentAlias)
{
Debug.Assert(currentAlias != null);

var uniqueAlias = currentAlias;
var counter = 0;

int _;
if (currentAlias.StartsWith(SystemAliasPrefix, StringComparison.Ordinal)
&& int.TryParse(currentAlias.Substring(1), out _))
{
currentAlias = SystemAliasPrefix;
}

while (_tables.Any(t => string.Equals(t.Alias, uniqueAlias, StringComparison.OrdinalIgnoreCase)))
{
uniqueAlias = currentAlias + counter++;
}

return uniqueAlias;
}

private string CreateUniqueProjectionAlias(string currentAlias)
{
var uniqueAlias = currentAlias ?? "A";
Expand Down
7 changes: 4 additions & 3 deletions src/Microsoft.EntityFrameworkCore.Relational/Query/Expressions/SelectExpressionFactory.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,13 @@ public SelectExpressionFactory([NotNull] IQuerySqlGeneratorFactory querySqlGener
_querySqlGeneratorFactory = querySqlGeneratorFactory;
}

public virtual SelectExpression Create()
=> new SelectExpression(_querySqlGeneratorFactory);
public virtual SelectExpression Create(RelationalQueryCompilationContext queryCompilationContext)
=> new SelectExpression(_querySqlGeneratorFactory, queryCompilationContext);

public virtual SelectExpression Create(string alias)
public virtual SelectExpression Create(RelationalQueryCompilationContext queryCompilationContext, string alias)
=> new SelectExpression(
_querySqlGeneratorFactory,
queryCompilationContext,
Check.NotEmpty(alias, nameof(alias)));
}
}
13 changes: 7 additions & 6 deletions ...icrosoft.EntityFrameworkCore.Relational/Query/Internal/RelationalResultOperatorHandler.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,8 @@ var predicate

if (predicate != null)
{
var innerSelectExpression = handlerContext.SelectExpressionFactory.Create();
var innerSelectExpression
= handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext);

innerSelectExpression.AddTables(handlerContext.SelectExpression.Tables);
innerSelectExpression.Predicate = Expression.Not(predicate);
Expand Down Expand Up @@ -194,7 +195,7 @@ var predicate

private static Expression HandleAny(HandlerContext handlerContext)
{
var innerSelectExpression = handlerContext.SelectExpressionFactory.Create();
var innerSelectExpression = handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext);

innerSelectExpression.AddTables(handlerContext.SelectExpression.Tables);
innerSelectExpression.Predicate = handlerContext.SelectExpression.Predicate;
Expand Down Expand Up @@ -235,14 +236,14 @@ var filteringVisitor

if (entityType != null)
{
var outterSelectExpression = handlerContext.SelectExpressionFactory.Create();
var outterSelectExpression = handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext);
outterSelectExpression.SetProjectionExpression(Expression.Constant(1));

var collectionSelectExpression
= handlerContext.SelectExpression.Clone(outterSelectExpression.CreateUniqueTableAlias());
= handlerContext.SelectExpression.Clone(handlerContext.QueryModelVisitor.QueryCompilationContext.CreateUniqueTableAlias());
outterSelectExpression.AddTable(collectionSelectExpression);

itemSelectExpression.Alias = outterSelectExpression.CreateUniqueTableAlias();
itemSelectExpression.Alias = handlerContext.QueryModelVisitor.QueryCompilationContext.CreateUniqueTableAlias();
var joinExpression = outterSelectExpression.AddInnerJoin(itemSelectExpression);

foreach (var property in entityType.FindPrimaryKey().Properties)
Expand Down Expand Up @@ -333,7 +334,7 @@ private static Expression HandleDefaultIfEmpty(HandlerContext handlerContext)

selectExpression.ClearTables();

var emptySelectExpression = handlerContext.SelectExpressionFactory.Create("empty");
var emptySelectExpression = handlerContext.SelectExpressionFactory.Create(handlerContext.QueryModelVisitor.QueryCompilationContext, "empty");
emptySelectExpression.AddToProjection(new AliasExpression("empty", Expression.Constant(null)));

selectExpression.AddTable(emptySelectExpression);
Expand Down
37 changes: 37 additions & 0 deletions src/Microsoft.EntityFrameworkCore.Relational/Query/RelationalQueryCompilationContext.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,9 @@

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text.RegularExpressions;
using JetBrains.Annotations;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Metadata;
Expand All @@ -20,6 +22,10 @@ public class RelationalQueryCompilationContext : QueryCompilationContext
private readonly List<RelationalQueryModelVisitor> _relationalQueryModelVisitors
= new List<RelationalQueryModelVisitor>();

private const string SystemAliasPrefix = "t";
private readonly IDictionary<string, int> _tableAliasCounterMap = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
private readonly ISet<string> _tableAliasSet = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

public RelationalQueryCompilationContext(
[NotNull] IModel model,
[NotNull] ISensitiveDataLogger logger,
Expand Down Expand Up @@ -78,5 +84,36 @@ public virtual SelectExpression FindSelectExpression([NotNull] IQuerySource quer
select selectExpression)
.First();
}

public virtual string CreateUniqueTableAlias()
=> CreateUniqueTableAlias(SystemAliasPrefix);

public virtual string CreateUniqueTableAlias([NotNull] string currentAlias)
{
Check.NotNull(currentAlias, nameof(currentAlias));

if (currentAlias.Length == 0)
{
return currentAlias;
}

var counter = 0;
var uniqueAlias = currentAlias;

if (_tableAliasCounterMap.ContainsKey(currentAlias))
{
counter = _tableAliasCounterMap[currentAlias];
uniqueAlias += counter;
}

while (_tableAliasSet.Contains(uniqueAlias))
{
uniqueAlias = currentAlias + counter++;
}
_tableAliasCounterMap[currentAlias] = counter;

_tableAliasSet.Add(uniqueAlias);
return uniqueAlias;
}
}
}
2 changes: 1 addition & 1 deletion ...tyFrameworkCore/Query/ExpressionVisitors/Internal/NavigationRewritingExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -324,7 +324,7 @@ private Expression CreateSubqueryForNavigations(

var mainFromClause
= new MainFromClause(
_queryModel.GetNewName("subQuery"),
"subQuery",
targetEntityType.ClrType, CreateEntityQueryable(targetEntityType));

var querySourceReference = new QuerySourceReferenceExpression(mainFromClause);
Expand Down
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