Support primitive collections

Closes dotnet#29427
Closes dotnet#30426
Closes dotnet#13617

Author: roji

All.sln.DotSettings

@@ -308,8 +308,10 @@ The .NET Foundation licenses this file to you under the MIT license.
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=navigations/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=niladic/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=NOCASE/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=OPENJSON/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=pluralizer/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Poolable/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Postgre/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=pushdown/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=remapper/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=requiredness/@EntryIndexedValue">True</s:Boolean>

src/EFCore.Relational/Properties/RelationalStrings.Designer.cs

@@ -346,6 +346,9 @@
   <data name="EitherOfTwoValuesMustBeNull" xml:space="preserve">
     <value>Either {param1} or {param2} must be null.</value>
   </data>
+  <data name="EmptyCollectionNotSupportedAsConstantQueryRoot" xml:space="preserve">
+    <value>Empty constant collections are not supported as constant query roots.</value>
+  </data>
   <data name="EntityShortNameNotUnique" xml:space="preserve">
     <value>The short name for '{entityType1}' is '{discriminatorValue}' which is the same for '{entityType2}'. Every concrete entity type in the hierarchy must have a unique short name. Either rename one of the types or call modelBuilder.Entity&lt;TEntity&gt;().Metadata.SetDiscriminatorValue("NewShortName").</value>
   </data>

src/EFCore.Relational/Properties/RelationalStrings.resx

@@ -57,11 +57,10 @@ public ContainsTranslator(ISqlExpressionFactory sqlExpressionFactory)
     }
 
     private static bool ValidateValues(SqlExpression values)
-        => values is SqlConstantExpression || values is SqlParameterExpression;
+        => values is SqlConstantExpression or SqlParameterExpression;
 
     private static SqlExpression RemoveObjectConvert(SqlExpression expression)
-        => expression is SqlUnaryExpression sqlUnaryExpression
-            && sqlUnaryExpression.OperatorType == ExpressionType.Convert
+        => expression is SqlUnaryExpression { OperatorType: ExpressionType.Convert } sqlUnaryExpression
             && sqlUnaryExpression.Type == typeof(object)
                 ? sqlUnaryExpression.Operand
                 : expression;

src/EFCore.Relational/Query/Internal/ContainsTranslator.cs

@@ -35,11 +35,11 @@ public SelectExpressionProjectionApplyingExpressionVisitor(QuerySplittingBehavio
     protected override Expression VisitExtension(Expression extensionExpression)
         => extensionExpression switch
         {
-            ShapedQueryExpression shapedQueryExpression
-                when shapedQueryExpression.QueryExpression is SelectExpression selectExpression
+            ShapedQueryExpression { QueryExpression: SelectExpression selectExpression } shapedQueryExpression
                 => shapedQueryExpression.UpdateShaperExpression(
                     selectExpression.ApplyProjection(
                         shapedQueryExpression.ShaperExpression, shapedQueryExpression.ResultCardinality, _querySplittingBehavior)),
+
             NonQueryExpression nonQueryExpression => nonQueryExpression,
             _ => base.VisitExtension(extensionExpression),
         };

src/EFCore.Relational/Query/Internal/SelectExpressionProjectionApplyingExpressionVisitor.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Runtime.CompilerServices;
 using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 using Microsoft.EntityFrameworkCore.Storage.Internal;
 
@@ -169,21 +168,22 @@ protected override Expression VisitSqlFragment(SqlFragmentExpression sqlFragment
     }
 
     private static bool IsNonComposedSetOperation(SelectExpression selectExpression)
-        => selectExpression.Offset == null
-            && selectExpression.Limit == null
-            && !selectExpression.IsDistinct
-            && selectExpression.Predicate == null
-            && selectExpression.Having == null
-            && selectExpression.Orderings.Count == 0
-            && selectExpression.GroupBy.Count == 0
-            && selectExpression.Tables.Count == 1
-            && selectExpression.Tables[0] is SetOperationBase setOperation
+        => selectExpression is
+            {
+                Tables: [SetOperationBase setOperation],
+                Offset: null,
+                Limit: null,
+                IsDistinct: false,
+                Predicate: null,
+                Having: null,
+                Orderings.Count: 0,
+                GroupBy.Count: 0
+            }
             && selectExpression.Projection.Count == setOperation.Source1.Projection.Count
             && selectExpression.Projection.Select(
                     (pe, index) => pe.Expression is ColumnExpression column
-                        && string.Equals(column.TableAlias, setOperation.Alias, StringComparison.Ordinal)
-                        && string.Equals(
-                            column.Name, setOperation.Source1.Projection[index].Alias, StringComparison.Ordinal))
+                        && column.TableAlias == setOperation.Alias
+                        && column.Name == setOperation.Source1.Projection[index].Alias)
                 .All(e => e);
 
     /// <inheritdoc />
@@ -226,12 +226,7 @@ protected override Expression VisitSelect(SelectExpression selectExpression)
             subQueryIndent = _relationalCommandBuilder.Indent();
         }
 
-        if (IsNonComposedSetOperation(selectExpression))
-        {
-            // Naked set operation
-            GenerateSetOperation((SetOperationBase)selectExpression.Tables[0]);
-        }
-        else
+        if (!TryGenerateWithoutWrappingSelect(selectExpression))
         {
             _relationalCommandBuilder.Append("SELECT ");
 
@@ -300,6 +295,43 @@ protected override Expression VisitSelect(SelectExpression selectExpression)
         return selectExpression;
     }
 
+    /// <summary>
+    ///     If possible, generates the expression contained within the provided <paramref name="selectExpression" /> without the wrapping
+    ///     SELECT. This can be done for set operations and VALUES, which can appear as top-level statements without needing to be wrapped
+    ///     in SELECT.
+    /// </summary>
+    protected virtual bool TryGenerateWithoutWrappingSelect(SelectExpression selectExpression)
+    {
+        if (IsNonComposedSetOperation(selectExpression))
+        {
+            GenerateSetOperation((SetOperationBase)selectExpression.Tables[0]);
+            return true;
+        }
+
+        if (selectExpression is
+            {
+                Tables: [ValuesExpression valuesExpression],
+                Offset: null,
+                Limit: null,
+                IsDistinct: false,
+                Predicate: null,
+                Having: null,
+                Orderings.Count: 0,
+                GroupBy.Count: 0,
+            }
+            && selectExpression.Projection.Count == valuesExpression.ColumnNames.Count
+            && selectExpression.Projection.Select(
+                    (pe, index) => pe.Expression is ColumnExpression column
+                        && column.Name == valuesExpression.ColumnNames[index])
+                .All(e => e))
+        {
+            GenerateValues(valuesExpression);
+            return true;
+        }
+
+        return false;
+    }
+
     /// <summary>
     ///     Generates a pseudo FROM clause. Required by some providers when a query has no actual FROM clause.
     /// </summary>
@@ -312,9 +344,7 @@ protected virtual void GeneratePseudoFromClause()
     /// </summary>
     /// <param name="selectExpression">SelectExpression for which the empty projection will be generated.</param>
     protected virtual void GenerateEmptyProjection(SelectExpression selectExpression)
-    {
-        _relationalCommandBuilder.Append("1");
-    }
+        => _relationalCommandBuilder.Append("1");
 
     /// <inheritdoc />
     protected override Expression VisitProjection(ProjectionExpression projectionExpression)
@@ -371,16 +401,16 @@ protected override Expression VisitSqlFunction(SqlFunctionExpression sqlFunction
     /// <inheritdoc />
     protected override Expression VisitTableValuedFunction(TableValuedFunctionExpression tableValuedFunctionExpression)
     {
-        if (!string.IsNullOrEmpty(tableValuedFunctionExpression.StoreFunction.Schema))
+        if (!string.IsNullOrEmpty(tableValuedFunctionExpression.Schema))
         {
             _relationalCommandBuilder
-                .Append(_sqlGenerationHelper.DelimitIdentifier(tableValuedFunctionExpression.StoreFunction.Schema))
+                .Append(_sqlGenerationHelper.DelimitIdentifier(tableValuedFunctionExpression.Schema))
                 .Append(".");
         }
 
-        var name = tableValuedFunctionExpression.StoreFunction.IsBuiltIn
-            ? tableValuedFunctionExpression.StoreFunction.Name
-            : _sqlGenerationHelper.DelimitIdentifier(tableValuedFunctionExpression.StoreFunction.Name);
+        var name = tableValuedFunctionExpression.IsBuiltIn
+            ? tableValuedFunctionExpression.Name
+            : _sqlGenerationHelper.DelimitIdentifier(tableValuedFunctionExpression.Name);
 
         _relationalCommandBuilder
             .Append(name)
@@ -607,6 +637,7 @@ protected override Expression VisitSqlParameter(SqlParameterExpression sqlParame
     {
         var invariantName = sqlParameterExpression.Name;
         var parameterName = sqlParameterExpression.Name;
+        var typeMapping = sqlParameterExpression.TypeMapping!;
 
         // Try to see if a parameter already exists - if so, just integrate the same placeholder into the SQL instead of sending the same
         // data twice.
@@ -615,11 +646,10 @@ protected override Expression VisitSqlParameter(SqlParameterExpression sqlParame
         var parameter = _relationalCommandBuilder.Parameters.FirstOrDefault(
             p =>
                 p.InvariantName == parameterName
-                && p is TypeMappedRelationalParameter typeMappedRelationalParameter
-                && string.Equals(
-                    typeMappedRelationalParameter.RelationalTypeMapping.StoreType, sqlParameterExpression.TypeMapping!.StoreType,
-                    StringComparison.OrdinalIgnoreCase)
-                && typeMappedRelationalParameter.RelationalTypeMapping.Converter == sqlParameterExpression.TypeMapping!.Converter);
+                && p is TypeMappedRelationalParameter { RelationalTypeMapping: var existingTypeMapping }
+                && string.Equals(existingTypeMapping.StoreType, typeMapping.StoreType, StringComparison.OrdinalIgnoreCase)
+                && (existingTypeMapping.Converter is null && typeMapping.Converter is null
+                    || existingTypeMapping.Converter is not null && existingTypeMapping.Converter.Equals(typeMapping.Converter)));
 
         if (parameter is null)
         {
@@ -1132,6 +1162,28 @@ protected override Expression VisitRowNumber(RowNumberExpression rowNumberExpres
         return rowNumberExpression;
     }
 
+    /// <inheritdoc />
+    protected override Expression VisitRowValue(RowValueExpression rowValueExpression)
+    {
+        Sql.Append("(");
+
+        var values = rowValueExpression.Values;
+        var count = values.Count;
+        for (var i = 0; i < count; i++)
+        {
+            if (i > 0)
+            {
+                Sql.Append(", ");
+            }
+
+            Visit(values[i]);
+        }
+
+        Sql.Append(")");
+
+        return rowValueExpression;
+    }
+
     /// <summary>
     ///     Generates a set operation in the relational command.
     /// </summary>
@@ -1141,18 +1193,16 @@ protected virtual void GenerateSetOperation(SetOperationBase setOperation)
         GenerateSetOperationOperand(setOperation, setOperation.Source1);
         _relationalCommandBuilder
             .AppendLine()
-            .Append(GetSetOperation(setOperation))
+            .Append(
+                setOperation switch
+                {
+                    ExceptExpression => "EXCEPT",
+                    IntersectExpression => "INTERSECT",
+                    UnionExpression => "UNION",
+                    _ => throw new InvalidOperationException(CoreStrings.UnknownEntity("SetOperationType"))
+                })
             .AppendLine(setOperation.IsDistinct ? string.Empty : " ALL");
         GenerateSetOperationOperand(setOperation, setOperation.Source2);
-
-        static string GetSetOperation(SetOperationBase operation)
-            => operation switch
-            {
-                ExceptExpression => "EXCEPT",
-                IntersectExpression => "INTERSECT",
-                UnionExpression => "UNION",
-                _ => throw new InvalidOperationException(CoreStrings.UnknownEntity("SetOperationType"))
-            };
     }
 
     /// <summary>
@@ -1311,6 +1361,66 @@ void LiftPredicate(TableExpressionBase joinTable)
             RelationalStrings.ExecuteOperationWithUnsupportedOperatorInSqlGeneration(nameof(RelationalQueryableExtensions.ExecuteUpdate)));
     }
 
+    /// <inheritdoc />
+    protected override Expression VisitValues(ValuesExpression valuesExpression)
+    {
+        _relationalCommandBuilder.Append("(");
+
+        GenerateValues(valuesExpression);
+
+        _relationalCommandBuilder
+            .Append(")")
+            .Append(AliasSeparator)
+            .Append(_sqlGenerationHelper.DelimitIdentifier(valuesExpression.Alias));
+
+        return valuesExpression;
+    }
+
+    /// <summary>
+    ///     Generates a VALUES expression.
+    /// </summary>
+    protected virtual void GenerateValues(ValuesExpression valuesExpression)
+    {
+        var rowValues = valuesExpression.RowValues;
+
+        // Some databases support providing the names of columns projected out of VALUES, e.g.
+        // SQL Server/PG: (VALUES (1, 3), (2, 4)) AS x(a, b). Others unfortunately don't; so by default, we extract out the first row,
+        // and generate a SELECT for it with the names, and a UNION ALL over the rest of the values.
+        _relationalCommandBuilder.Append("SELECT ");
+
+        Check.DebugAssert(rowValues.Count > 0, "rowValues.Count > 0");
+        var firstRowValues = rowValues[0].Values;
+        for (var i = 0; i < firstRowValues.Count; i++)
+        {
+            if (i > 0)
+            {
+                _relationalCommandBuilder.Append(", ");
+            }
+
+            Visit(firstRowValues[i]);
+
+            _relationalCommandBuilder
+                .Append(AliasSeparator)
+                .Append(_sqlGenerationHelper.DelimitIdentifier(valuesExpression.ColumnNames[i]));
+        }
+
+        if (rowValues.Count > 1)
+        {
+            _relationalCommandBuilder.Append(" UNION ALL VALUES ");
+
+            for (var i = 1; i < rowValues.Count; i++)
+            {
+                // TODO: Do we want newlines here?
+                if (i > 1)
+                {
+                    _relationalCommandBuilder.Append(", ");
+                }
+
+                Visit(valuesExpression.RowValues[i]);
+            }
+        }
+    }
+
     /// <inheritdoc />
     protected override Expression VisitJsonScalar(JsonScalarExpression jsonScalarExpression)
         => throw new InvalidOperationException(