Merge pull request #1 from zhelgadis/select_modeling

Added Selection and Projection classes

Code/Epic.Query/Epic.Query.csproj

@@ -62,6 +62,8 @@
     <Compile Include="..\EpicInfo.cs">
       <Link>EpicInfo.cs</Link>
     </Compile>
+    <Compile Include="Relational\Operations\Projection.cs" />
+    <Compile Include="Relational\Operations\Selection.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
@@ -70,4 +72,7 @@
       <Name>Epic.Prelude</Name>
     </ProjectReference>
   </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Relational\Operations\" />
+  </ItemGroup>
 </Project>

Code/Epic.Query/Relational/Operations/Projection.cs

@@ -0,0 +1,189 @@
+//  
+//  Projection.cs
+//  
+//  Author:
+//       Marco Veglio <m.veglio@gmail.com>
+// 
+//  Copyright (c) 2010-2012 Giacomo Tesio
+// 
+//  This file is part of Epic.NET.
+// 
+//  Epic.NET is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU Affero General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+// 
+//  Epic.NET is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU Affero General Public License for more details.
+// 
+//  You should have received a copy of the GNU Affero General Public License
+//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//  
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+
+namespace Epic.Query.Relational.Operations
+{
+    /// <summary>
+    /// This class models the Projection operation, which extracts a given set of fields from a given
+    /// <see cref="Relation"/>.
+    /// </summary>
+    [Serializable]
+    public sealed class Projection: Relation, IEquatable<Projection>
+    {
+        private readonly Relation relation;
+        private readonly IEnumerable<RelationAttribute> attributes;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Epic.Query.Relational.Operations.Projection"/> class.
+        /// </summary>
+        /// <param name='relation'>
+        /// The <see cref="Relation"/> used as source for the projection.
+        /// </param>
+        /// <param name='attributes'>
+        /// The collection of <see cref="RelationAttributes"/> extracted
+        /// </param>
+        /// <param name='name'>
+        /// A user-defined name used to identify the Projection relation.
+        /// </param>
+        public Projection (Relation relation, IEnumerable<RelationAttribute> attributes, string name):
+            base(RelationType.Projection, name)
+        {
+            if (null == relation) throw new ArgumentNullException("relation");
+            if (null == attributes) throw new ArgumentNullException("attributes");
+            if (null == name) throw new ArgumentNullException("name");
+            this.relation = relation;
+            this.attributes = attributes;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Epic.Query.Relational.Operations.Projection"/> class.
+        /// </summary>
+        /// <param name='relation'>
+        /// The <see cref="Relation"/> used as source for the projection.
+        /// </param>
+        /// <param name='attributes'>
+        /// The collection of <see cref="RelationAttributes"/> extracted
+        /// </param>
+        public Projection(Relation relation, IEnumerable<RelationAttribute> attributes):
+            base(RelationType.Projection, getDefaultName(relation, attributes))
+        {
+            if (null == relation) throw new ArgumentNullException("relation");
+            if (null == attributes) throw new ArgumentNullException("attributes");
+            this.relation = relation;
+            this.attributes = attributes;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="Relation"/> used as source for the projection.
+        /// </summary>
+        /// <value>
+        /// The table.
+        /// </value>
+        public Relation Relation { get { return this.relation; } }
+
+        /// <summary>
+        /// Gets the attributes extracted from the given table.
+        /// </summary>
+        /// <value>
+        /// The attributes.
+        /// </value>
+        public IEnumerable<RelationAttribute> Attributes { get { return this.attributes; } }
+
+        /// <summary>
+        /// Determines whether the specified <see cref="Epic.Query.Relational.Relation"/> is equal to the current <see cref="Epic.Query.Relational.Operations.Projection"/>.
+        /// </summary>
+        /// <param name='other'>
+        /// The <see cref="Epic.Query.Relational.Relation"/> to compare with the current <see cref="Epic.Query.Relational.Operations.Projection"/>.
+        /// </param>
+        /// <returns>
+        /// <c>true</c> if the specified <see cref="Epic.Query.Relational.Relation"/> is equal to the current
+        /// <see cref="Epic.Query.Relational.Operations.Projection"/>; otherwise, <c>false</c>.
+        /// </returns>
+        public override bool Equals (Relation other)
+        {
+            return this.Equals (other as Projection);
+        }
+
+        /// <summary>
+        /// Determines whether the specified <see cref="Epic.Query.Relational.Operations.Projection"/> is equal to the
+        /// current <see cref="Epic.Query.Relational.Operations.Projection"/>.
+        /// </summary>
+        /// <param name='other'>
+        /// The <see cref="Epic.Query.Relational.Operations.Projection"/> to compare with the current <see cref="Epic.Query.Relational.Operations.Projection"/>.
+        /// </param>
+        /// <returns>
+        /// <c>true</c> if the specified <see cref="Epic.Query.Relational.Operations.Projection"/> is equal to the
+        /// current <see cref="Epic.Query.Relational.Operations.Projection"/>; otherwise, <c>false</c>.
+        /// </returns>
+        public bool Equals(Projection other)
+        {
+            if (null == other) return false;
+            return this.Relation.Equals (other.Relation) && this.Attributes.SequenceEqual(other.Attributes);
+        }
+
+        /// <summary>
+        /// Accept the specified visitor and context.
+        /// </summary>
+        /// <param name='visitor'>
+        /// Visitor.
+        /// </param>
+        /// <param name='context'>
+        /// Context.
+        /// </param>
+        /// <typeparam name='TResult'>
+        /// The 1st type parameter.
+        /// </typeparam>
+        public override TResult Accept<TResult> (IVisitor<TResult> visitor, IVisitContext context)
+        {
+            return AcceptMe (this, visitor, context);
+        }
+
+        /// <summary>
+        /// Serves as a hash function for a <see cref="Epic.Query.Relational.Operations.Projection"/> object.
+        /// </summary>
+        /// <returns>
+        /// A hash code for this instance that is suitable for use in hashing algorithms and data structures such as a
+        /// hash table.
+        /// </returns>
+        public override int GetHashCode ()
+        {
+            int hash = this.Relation.GetHashCode ();
+            foreach (RelationAttribute attribute in this.Attributes)
+                hash ^= attribute.GetHashCode ();
+            return hash;
+        }
+
+        /// <summary>
+        /// Gets the default name for the projection.
+        /// </summary>
+        /// <returns>
+        /// The default name.
+        /// </returns>
+        /// <param name='relation'>
+        /// the <see cref="Relation"/> used as source for the projection.
+        /// </param>
+        /// <param name='attributes'>
+        /// The attributes to be extracted from the relation.
+        /// </param>
+        private static string getDefaultName (Relation relation, IEnumerable<RelationAttribute> attributes)
+        {
+            if (null == relation) throw new ArgumentNullException("relation");
+            if (null == attributes) throw new ArgumentNullException("attributes");
+            StringBuilder sb = new StringBuilder();
+            sb.Append("Take ");
+            foreach (RelationAttribute attribute in attributes)
+                sb.Append (attribute.Name).Append(",");
+            sb.Append (" from ");
+            sb.Append (relation.Name);
+            return sb.ToString ();
+        }
+
+    }
+}
+

Code/Epic.Query/Relational/Operations/Selection.cs

@@ -0,0 +1,176 @@
+//  
+//  Select.cs
+//  
+//  Author:
+//       Marco Veglio <m.veglio@gmail.com>
+// 
+//  Copyright (c) 2010-2012 Giacomo Tesio
+// 
+//  This file is part of Epic.NET.
+// 
+//  Epic.NET is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU Affero General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+// 
+//  Epic.NET is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU Affero General Public License for more details.
+// 
+//  You should have received a copy of the GNU Affero General Public License
+//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//  
+using System;
+using Epic.Query.Relational.Predicates;
+
+namespace Epic.Query.Relational.Operations
+{
+
+    /// <summary>
+    /// This class models the Select operation which extracts those record from a given table matching
+    /// a given <see cref="Predicate"/>
+    /// </summary>
+    [Serializable]
+    public sealed class Selection: Relation, IEquatable<Selection>
+    {
+        private readonly Predicate condition;
+        private readonly Relation relation;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Epic.Query.Relational.Operations.Selection"/> class.
+        /// </summary>
+        /// <param name='relation'>
+        /// The <see cref="Relation"/> used as source for the selection.
+        /// </param>
+        /// <param name='condition'>
+        /// The <see cref="Predicate"/> against which the records are matched.
+        /// </param>
+        public Selection (Relation relation, Predicate condition): 
+            base(RelationType.Selection, getDefaultName (relation, condition))
+        {
+            if (null == relation) throw new ArgumentNullException("relation");
+            if (null == condition) throw new ArgumentNullException("condition");
+            this.condition = condition;
+            this.relation = relation;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Epic.Query.Relational.Operations.Selection"/> class.
+        /// </summary>
+        /// <param name='relation'>
+        /// The table used as source for the selection.
+        /// </param>
+        /// <param name='condition'>
+        /// The <see cref="Predicate"/> against which the records are matched.
+        /// </param>
+        /// <param name='name'>
+        /// A user-defined name to identify the Selection relation.
+        /// </param>
+        public Selection (Relation relation, Predicate condition, string name): base(RelationType.Selection, name)
+        {
+            if (null == relation) throw new ArgumentNullException("relation");
+            if (null == condition) throw new ArgumentNullException("condition");
+            if (null == name) throw new ArgumentNullException("name");
+            this.condition = condition;
+            this.relation = relation;
+        }
+
+        /// <summary>
+        /// Gets the condition against which the table's records are matched.
+        /// </summary>
+        /// <value>
+        /// The condition.
+        /// </value>
+        public Predicate Condition { get { return this.condition; } }
+
+        /// <summary>
+        /// Gets the <see cref="Relation"/> used as source for the selection.
+        /// </summary>
+        /// <value>
+        /// The table.
+        /// </value>
+        public Relation Relation { get { return this.relation; } }
+
+        /// <summary>
+        /// Determines whether the specified <see cref="Epic.Query.Relational.Relation"/> is equal to the current <see cref="Epic.Query.Relational.Operations.Selection"/>.
+        /// </summary>
+        /// <param name='other'>
+        /// The <see cref="Epic.Query.Relational.Relation"/> to compare with the current <see cref="Epic.Query.Relational.Operations.Selection"/>.
+        /// </param>
+        /// <returns>
+        /// <c>true</c> if the specified <see cref="Epic.Query.Relational.Relation"/> is equal to the current
+        /// <see cref="Epic.Query.Relational.Operations.Selection"/>; otherwise, <c>false</c>.
+        /// </returns>
+        public override bool Equals (Relation other)
+        {
+            return this.Equals (other as Selection);
+        }
+
+        /// <summary>
+        /// Determines whether the specified <see cref="Epic.Query.Relational.Operations.Selection"/> is equal to the
+        /// current <see cref="Epic.Query.Relational.Operations.Selection"/>.
+        /// </summary>
+        /// <param name='other'>
+        /// The <see cref="Epic.Query.Relational.Operations.Selection"/> to compare with the current <see cref="Epic.Query.Relational.Operations.Selection"/>.
+        /// </param>
+        /// <returns>
+        /// <c>true</c> if the specified <see cref="Epic.Query.Relational.Operations.Selection"/> is equal to the current
+        /// <see cref="Epic.Query.Relational.Operations.Selection"/>; otherwise, <c>false</c>.
+        /// </returns>
+        public bool Equals(Selection other)
+        {
+            if (null == other) return false;
+            return this.Relation.Equals (other.Relation) && this.Condition.Equals (other.Condition);
+        }
+
+        /// <summary>
+        /// Serves as a hash function for a <see cref="Epic.Query.Relational.Operations.Selection"/> object.
+        /// </summary>
+        /// <returns>
+        /// A hash code for this instance that is suitable for use in hashing algorithms and data structures such as a
+        /// hash table.
+        /// </returns>
+        public override int GetHashCode ()
+        {
+            return this.Relation.GetHashCode () ^ this.Condition.GetHashCode ();
+        }
+
+        /// <summary>
+        /// Accept the specified visitor and context.
+        /// </summary>
+        /// <param name='visitor'>
+        /// Visitor.
+        /// </param>
+        /// <param name='context'>
+        /// Context.
+        /// </param>
+        /// <typeparam name='TResult'>
+        /// The 1st type parameter.
+        /// </typeparam>
+        public override TResult Accept<TResult> (IVisitor<TResult> visitor, IVisitContext context)
+        {
+            return AcceptMe (this, visitor, context);
+        }
+
+        /// <summary>
+        /// Gets the default name for the selection.
+        /// </summary>
+        /// <returns>
+        /// The default name.
+        /// </returns>
+        /// <param name='relation'>
+        /// The <see cref="Relation"/> used as source for the selection.
+        /// </param>
+        /// <param name='predicate'>
+        /// The condition against which the records are matched.
+        /// </param>
+        private static string getDefaultName(Relation relation, Predicate predicate)
+        {
+            if (null == relation) throw new ArgumentNullException("relation");
+            if (null == predicate) throw new ArgumentNullException("predicate");
+            return string.Format ("SELECT * from {0} where {1}", relation.Name, predicate.ToString ());
+        }
+    }
+}
+

Code/UnitTests/Epic.Query.UnitTests/Epic.Query.UnitTests.csproj

@@ -76,8 +76,11 @@
     <Compile Include="Fakes\FakeRelationFunction.cs" />
     <Compile Include="Fakes\FakeScalar.cs" />
     <Compile Include="Fakes\FakeScalarFunction.cs" />
+    <Compile Include="Relational\Operations\SelectionQA.cs" />
+    <Compile Include="Relational\Operations\ProjectionQA.cs" />
   </ItemGroup>
   <ItemGroup>
     <Folder Include="Fakes\" />
+    <Folder Include="Relational\Operations\" />
   </ItemGroup>
 </Project>