From 68e8b6f1716473fef696c6eb627d67772f2f0fca Mon Sep 17 00:00:00 2001
From: sergergood <serzher@inbox.ru>
Date: Wed, 31 Jan 2024 14:31:45 +0300
Subject: [PATCH] Using  FrozenDictionary

---
 .../RepoDb/Cachers/Types/DbFieldCollection.cs   | 17 +++++++++--------
 RepoDb.Core/RepoDb/RepoDb.csproj                |  4 ++++
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/RepoDb.Core/RepoDb/Cachers/Types/DbFieldCollection.cs b/RepoDb.Core/RepoDb/Cachers/Types/DbFieldCollection.cs
index 473044668..610688fd6 100644
--- a/RepoDb.Core/RepoDb/Cachers/Types/DbFieldCollection.cs
+++ b/RepoDb.Core/RepoDb/Cachers/Types/DbFieldCollection.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.Linq;
 using RepoDb.Extensions;
@@ -15,8 +16,8 @@ public class DbFieldCollection
     private readonly IReadOnlyList<DbField> dbFields;
     private readonly Lazy<IEnumerable<Field>> lazyFields;
     private readonly Lazy<DbField> lazyIdentity;
-    private readonly Lazy<Dictionary<string, DbField>> lazyMapByName;
-    private readonly Lazy<Dictionary<string, DbField>> lazyMapByUnquotedName;
+    private readonly Lazy<FrozenDictionary<string, DbField>> lazyMapByName;
+    private readonly Lazy<FrozenDictionary<string, DbField>> lazyMapByUnquotedName;
     private readonly Lazy<DbField> lazyPrimary;
 
     /// <summary>
@@ -31,8 +32,8 @@ public DbFieldCollection(IEnumerable<DbField> dbFields, IDbSetting dbSetting)
 
         lazyPrimary = new Lazy<DbField>(GetPrimaryDbField);
         lazyIdentity = new Lazy<DbField>(GetIdentityDbField);
-        lazyMapByName = new Lazy<Dictionary<string, DbField>>(GetDbFieldsMappedByName);
-        lazyMapByUnquotedName = new Lazy<Dictionary<string, DbField>>(GetDbFieldsMappedByUnquotedName);
+        lazyMapByName = new Lazy<FrozenDictionary<string, DbField>>(GetDbFieldsMappedByName);
+        lazyMapByUnquotedName = new Lazy<FrozenDictionary<string, DbField>>(GetDbFieldsMappedByUnquotedName);
         lazyFields = new Lazy<IEnumerable<Field>>(GetDbFieldsAsFields);
     }
     
@@ -90,11 +91,11 @@ public DbField GetByUnquotedName(string name)
         return dbField;
     }
 
-    private Dictionary<string, DbField> GetDbFieldsMappedByName() => 
-        dbFields.ToDictionary(df => df.Name, df => df, StringComparer.OrdinalIgnoreCase);
+    private FrozenDictionary<string, DbField> GetDbFieldsMappedByName() => 
+        dbFields.ToFrozenDictionary(df => df.Name, df => df, StringComparer.OrdinalIgnoreCase);
 
-    private Dictionary<string, DbField> GetDbFieldsMappedByUnquotedName() =>
-        dbFields.ToDictionary(df => df.Name.AsUnquoted(true, dbSetting), df => df, StringComparer.OrdinalIgnoreCase);
+    private FrozenDictionary<string, DbField> GetDbFieldsMappedByUnquotedName() =>
+        dbFields.ToFrozenDictionary(df => df.Name.AsUnquoted(true, dbSetting), df => df, StringComparer.OrdinalIgnoreCase);
 
     private DbField GetPrimaryDbField() => dbFields.FirstOrDefault(df => df.IsPrimary);
 
diff --git a/RepoDb.Core/RepoDb/RepoDb.csproj b/RepoDb.Core/RepoDb/RepoDb.csproj
index 73ba09b1b..b1985ed7c 100644
--- a/RepoDb.Core/RepoDb/RepoDb.csproj
+++ b/RepoDb.Core/RepoDb/RepoDb.csproj
@@ -39,6 +39,10 @@
 		<PackageReference Include="System.Memory" Version="4.5.5" />
 	</ItemGroup>
 
+	<ItemGroup Condition="'$(TargetFramework)' != 'net8.0'">
+		<PackageReference Include="System.Collections.Immutable" Version="8.0.0" />
+	</ItemGroup>
+
 	<ItemGroup>
 		<None Include="..\..\LICENSE.txt">
 			<Pack>True</Pack>