Better handling for IsUnicode.

Author: cincuranet

src/FirebirdSql.EntityFrameworkCore.Firebird/Query/Internal/FbQuerySqlGenerator.cs

@@ -114,7 +114,8 @@ protected override Expression VisitSqlParameter(SqlParameterExpression sqlParame
 			Sql.Append(" AS ");
 			if (sqlParameterExpression.Type == typeof(string))
 			{
-				Sql.Append(((IFbSqlGenerationHelper)Dependencies.SqlGenerationHelper).StringParameterQueryType());
+				var isUnicode = FbTypeMappingSource.IsUnicode(sqlParameterExpression.TypeMapping);
+				Sql.Append(((IFbSqlGenerationHelper)Dependencies.SqlGenerationHelper).StringParameterQueryType(isUnicode));
 			}
 			else
 			{

src/FirebirdSql.EntityFrameworkCore.Firebird/Storage/Internal/FbSqlGenerationHelper.cs

@@ -30,13 +30,14 @@ public FbSqlGenerationHelper(RelationalSqlGenerationHelperDependencies dependenc
 	public virtual string StringLiteralQueryType(string s)
 	{
 		var length = MinimumStringQueryTypeLength(s);
-		EnsureStringQueryTypeLength(length);
+		EnsureStringLiteralQueryTypeLength(length);
 		return $"VARCHAR({length}) CHARACTER SET UTF8";
 	}
 
-	public virtual string StringParameterQueryType()
+	public virtual string StringParameterQueryType(bool isUnicode)
 	{
-		return $"VARCHAR({FbTypeMappingSource.VarcharMaxSize})";
+		var size = isUnicode ? FbTypeMappingSource.UnicodeVarcharMaxSize : FbTypeMappingSource.VarcharMaxSize;
+		return $"VARCHAR({size})";
 	}
 
 	public virtual void GenerateBlockParameterName(StringBuilder builder, string name)
@@ -54,9 +55,9 @@ static int MinimumStringQueryTypeLength(string s)
 		return length;
 	}
 
-	static void EnsureStringQueryTypeLength(int length)
+	static void EnsureStringLiteralQueryTypeLength(int length)
 	{
-		if (length > FbTypeMappingSource.VarcharMaxSize)
+		if (length > FbTypeMappingSource.UnicodeVarcharMaxSize)
 			throw new ArgumentOutOfRangeException(nameof(length));
 	}
 }

src/FirebirdSql.EntityFrameworkCore.Firebird/Storage/Internal/FbTypeMappingSource.cs

@@ -27,7 +27,8 @@ namespace FirebirdSql.EntityFrameworkCore.Firebird.Storage.Internal;
 public class FbTypeMappingSource : RelationalTypeMappingSource
 {
 	public const int BinaryMaxSize = Int32.MaxValue;
-	public const int VarcharMaxSize = 32765 / 4;
+	public const int UnicodeVarcharMaxSize = VarcharMaxSize / 4;
+	public const int VarcharMaxSize = 32765;
 	public const int DefaultDecimalPrecision = 18;
 	public const int DefaultDecimalScale = 2;
 
@@ -133,7 +134,7 @@ RelationalTypeMapping FindRawMapping(RelationalTypeMappingInfo mappingInfo)
 		var clrType = mappingInfo.ClrType;
 		var storeTypeName = mappingInfo.StoreTypeName;
 		var storeTypeNameBase = mappingInfo.StoreTypeNameBase;
-		var isUnicode = mappingInfo.IsUnicode ?? true;
+		var isUnicode = IsUnicode(mappingInfo.IsUnicode);
 
 		if (storeTypeName != null)
 		{
@@ -165,10 +166,11 @@ RelationalTypeMapping FindRawMapping(RelationalTypeMappingInfo mappingInfo)
 			{
 				var isFixedLength = mappingInfo.IsFixedLength == true;
 				var size = mappingInfo.Size ?? (mappingInfo.IsKeyOrIndex ? 256 : (int?)null);
+				var maxSize = isUnicode ? UnicodeVarcharMaxSize : VarcharMaxSize;
 
-				if (size > VarcharMaxSize)
+				if (size > maxSize)
 				{
-					size = isFixedLength ? VarcharMaxSize : (int?)null;
+					size = isFixedLength ? maxSize : (int?)null;
 				}
 
 				if (size == null)
@@ -196,4 +198,8 @@ RelationalTypeMapping FindRawMapping(RelationalTypeMappingInfo mappingInfo)
 
 		return null;
 	}
+
+	public static bool IsUnicode(RelationalTypeMapping mapping) => IsUnicode(mapping?.IsUnicode);
+	public static bool IsUnicode(RelationalTypeMappingInfo mappingInfo) => IsUnicode(mappingInfo.IsUnicode);
+	public static bool IsUnicode(bool? isUnicode) => isUnicode ?? true;
 }

src/FirebirdSql.EntityFrameworkCore.Firebird/Storage/Internal/IFbSqlGenerationHelper.cs

@@ -23,7 +23,7 @@ namespace FirebirdSql.EntityFrameworkCore.Firebird.Storage.Internal;
 public interface IFbSqlGenerationHelper : ISqlGenerationHelper
 {
 	string StringLiteralQueryType(string s);
-	string StringParameterQueryType();
+	string StringParameterQueryType(bool isUnicode);
 	void GenerateBlockParameterName(StringBuilder builder, string name);
 	string AlternativeStatementTerminator { get; }
 }