More changes for default collations.

- Changed CollateAttribute to use Collation internally.
- Throw an exception when CollateAttribute has been used on a non-string property.
- Added a line about default collations to the readme.

Author: magnusbakken-zetadisplay

README.md

@@ -27,6 +27,7 @@ The following features are supported:
 - Index (Decorate columns with the `Index` attribute. Indices are automatically created for foreign keys by default. To prevent this you can remove the convention `ForeignKeyIndexConvention`)
 - Unique constraint (Decorate columns with the `UniqueAttribute`, which is part of this library)
 - Collate constraint (Decorate columns with the `CollateAttribute`, which is part of this library. Use `CollationFunction.Custom` to specify a own collation function.)
+- Default collation (pass an instance of Collation as constructor parameter for an initializer to specify a default collation).
 - SQL default value (Decorate columns with the `SqlDefaultValueAttribute`, which is part of this library)
 
 ## Install

SQLite.CodeFirst.Test/IntegrationTests/SqlGenerationDefaultCollationTest.cs

@@ -57,7 +57,7 @@ public void SqliteSqlGeneratorWithDefaultCollationTest()
                 // This is important! Else the in memory database will not work.
                 connection.Open();
 
-                var defaultCollation = new Collation() { CollationFunction = CollationFunction.Custom, Function = "custom_collate" };
+                var defaultCollation = new Collation() { Function = CollationFunction.Custom, CustomFunction  = "custom_collate" };
                 using (var context = new DummyDbContext(connection, defaultCollation))
                 {
                     // ReSharper disable once UnusedVariable

SQLite.CodeFirst/Internal/Builder/ColumnStatementCollectionBuilder.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Data.Entity.Core.Metadata.Edm;
 using System.Linq;
 using SQLite.CodeFirst.Extensions;
@@ -77,17 +78,23 @@ private static void AddNullConstraintIfNecessary(EdmProperty property, ColumnSta
 
         private static void AddCollationConstraintIfNecessary(EdmProperty property, ColumnStatement columnStatement, Collation defaultCollation)
         {
-            if (property.PrimitiveType.PrimitiveTypeKind != PrimitiveTypeKind.String)
+            var collateAttribute = property.GetCustomAnnotation<CollateAttribute>();
+            if (property.PrimitiveType.PrimitiveTypeKind == PrimitiveTypeKind.String)
             {
-                return;
+                // The column is a string type. Check if we have an explicit or default collation.
+                // If we have both, the explicitly chosen collation takes precedence.
+                var value = collateAttribute == null ? defaultCollation : collateAttribute.Collation;
+                if (value != null)
+                {
+                    columnStatement.ColumnConstraints.Add(new CollateConstraint { CollationFunction = value.Function, CustomCollationFunction = value.CustomFunction });
+                }
             }
-
-            var collateAttribute = property.GetCustomAnnotation<CollateAttribute>();
-            var value = collateAttribute == null ? defaultCollation : collateAttribute.CollationData;
-
-            if (value != null)
+            else if (collateAttribute != null)
             {
-                columnStatement.ColumnConstraints.Add(new CollateConstraint { CollationFunction = value.CollationFunction, CustomCollationFunction = value.Function });
+                // Only string columns can be explicitly decorated with CollateAttribute.
+                var name = $"{property.DeclaringType.Name}.{property.Name}";
+                var errorMessage = $"CollateAttribute cannot be used on non-string property: {name} (underlying type is {property.PrimitiveType.PrimitiveTypeKind})";
+                throw new InvalidOperationException(errorMessage);
             }
         }
 

SQLite.CodeFirst/Public/Attributes/CollateAttribute.cs

@@ -11,39 +11,20 @@ namespace SQLite.CodeFirst
     public sealed class CollateAttribute : Attribute
     {
         public CollateAttribute()
-            : this(CollationFunction.None)
         {
+            Collation = new Collation();
         }
 
-        public CollateAttribute(CollationFunction collation)
-            : this(collation, null)
+        public CollateAttribute(CollationFunction function)
         {
+            Collation = new Collation(function);
         }
 
-        public CollateAttribute(CollationFunction collation, string function)
+        public CollateAttribute(CollationFunction function, string customFunction)
         {
-            if (collation != CollationFunction.Custom && !string.IsNullOrEmpty(function))
-            {
-                throw new ArgumentException("If the collation is not set to CollationFunction.Custom a function must not be specified.", nameof(function));
-            }
-
-            if (collation == CollationFunction.Custom && string.IsNullOrEmpty(function))
-            {
-                throw new ArgumentException("If the collation is set to CollationFunction.Custom a function must be specified.", nameof(function));
-            }
-
-            Collation = collation;
-            Function = function;
-            CollationData = new Collation() { CollationFunction = collation, Function = function };
+            Collation = new Collation(function, customFunction);
         }
 
-        public CollationFunction Collation { get; }
-
-        /// <summary>
-        /// The name of the custom collating function to use (CollationFunction.Custom).
-        /// </summary>
-        public string Function { get; }
-
-        public Collation CollationData { get; }
+        public Collation Collation { get; }
     }
 }

SQLite.CodeFirst/Public/Collation.cs

@@ -1,18 +1,46 @@
-namespace SQLite.CodeFirst
+using System;
+
+namespace SQLite.CodeFirst
 {
     /// <summary>
     /// This class can be used to specify the default collation for the database. Explicit Collate attributes will take precendence.
     /// When SQLite compares two strings, it uses a collating sequence or collating function (two words for the same thing)
-    /// to determine which string is greater or if the two strings are equal. SQLite has three built-in collating functions (see <see cref="CollationFunction"/>).
-    /// Set  <see cref="CollationFunction"/> to <see cref="CollationFunction.Custom"/> and specify the name using the function parameter.
+    /// to determine which string is greater or if the two strings are equal. SQLite has three built-in collating functions (see <see cref="Function"/>).
+    /// Set  <see cref="Function"/> to <see cref="CollationFunction.Custom"/> and specify the name using the function parameter.
     /// </summary>
     public class Collation
     {
-        public CollationFunction CollationFunction { get; set; }
+        public Collation()
+            : this(CollationFunction.None)
+        {
+        }
+
+        public Collation(CollationFunction function)
+            : this(function, null)
+        {
+        }
+
+        public Collation(CollationFunction function, string customFunction)
+        {
+            if (function != CollationFunction.Custom && !string.IsNullOrEmpty(customFunction))
+            {
+                throw new ArgumentException("If the collation is not set to CollationFunction.Custom a function must not be specified.", nameof(function));
+            }
+
+            if (function == CollationFunction.Custom && string.IsNullOrEmpty(customFunction))
+            {
+                throw new ArgumentException("If the collation is set to CollationFunction.Custom a function must be specified.", nameof(function));
+            }
+
+            CustomFunction  = customFunction;
+            Function = function;
+        }
+
+        public CollationFunction Function { get; set; }
 
         /// <summary>
         /// The name of the custom collating function to use (CollationFunction.Custom).
         /// </summary>
-        public string Function { get; set; }
+        public string CustomFunction  { get; set; }
     }
 }