Add new opt-in SqlServerParameterizedSqlExpression, enable with OrmLiteConfig.UseParameterizeSqlExpressions

Author: mythz

src/ServiceStack.OrmLite.SqlServer/SqlServerExpression.cs

@@ -3,56 +3,106 @@
 
 namespace ServiceStack.OrmLite.SqlServer
 {
-	public class SqlServerExpression<T> : SqlExpression<T>
-	{
+    public class SqlServerExpression<T> : SqlExpression<T>
+    {
         public SqlServerExpression(IOrmLiteDialectProvider dialectProvider)
             : base(dialectProvider) {}
 
         public override string ToUpdateStatement(T item, bool excludeDefaults = false)
         {
+            return SqlServerExpressionUtils.ToSqlServerUpdateStatement(this, item, excludeDefaults);
+        }
+
+        public override string GetSubstringSql(object quotedColumn, int startIndex, int? length = null)
+        {
+            return length != null
+                ? string.Format("substring({0}, {1}, {2})", quotedColumn, startIndex, length.Value)
+                : string.Format("substring({0}, {1}, LEN({0}) - {1} + 1)", quotedColumn, startIndex);
+        }
+
+        public override SqlExpression<T> OrderByRandom()
+        {
+            return base.OrderBy("NEWID()");
+        }
+    }
+
+    public class SqlServerParameterizedSqlExpression<T> : ParameterizedSqlExpression<T>
+    {
+        public SqlServerParameterizedSqlExpression(IOrmLiteDialectProvider dialectProvider)
+            : base(dialectProvider) {}
+
+        public override string ToUpdateStatement(T item, bool excludeDefaults = false)
+        {
+            return SqlServerExpressionUtils.ToSqlServerUpdateStatement(this, item, excludeDefaults);
+        }
+
+        public override string GetSubstringSql(object quotedColumn, int startIndex, int? length = null)
+        {
+            return length != null
+                ? string.Format("substring({0}, {1}, {2})", quotedColumn, startIndex, length.Value)
+                : string.Format("substring({0}, {1}, LEN({0}) - {1} + 1)", quotedColumn, startIndex);
+        }
+
+        public override SqlExpression<T> OrderByRandom()
+        {
+            return base.OrderBy("NEWID()");
+        }
+
+        protected override void ConvertToPlaceholderAndParameter(ref object right)
+        {
+            var paramName = Params.Count.ToString();
+            var paramValue = right;
+            var parameter = CreateParam(paramName, paramValue);
+
+            // Prevents a new plan cache for each different string length. Every string is parameterized as NVARCHAR(max) 
+            if (parameter.DbType == System.Data.DbType.String)
+                parameter.Size = -1;
+
+            Params.Add(parameter);
+
+            right = parameter.ParameterName;
+        }
+    }
+
+    internal class SqlServerExpressionUtils
+    {
+        internal static string ToSqlServerUpdateStatement<T>(SqlExpression<T> q, T item, bool excludeDefaults = false)
+        {
+            var modelDef = q.ModelDef;
+            var dialectProvider = q.DialectProvider;
+
             var setFields = new StringBuilder();
 
-            foreach (var fieldDef in ModelDef.FieldDefinitions)
+            foreach (var fieldDef in modelDef.FieldDefinitions)
             {
                 if (fieldDef.ShouldSkipUpdate()) continue;
                 if (fieldDef.IsRowVersion) continue;
-                if (UpdateFields.Count > 0 
-                    && !UpdateFields.Contains(fieldDef.Name) 
-                    || fieldDef.AutoIncrement) continue; // added
+                if (q.UpdateFields.Count > 0
+                    && !q.UpdateFields.Contains(fieldDef.Name)
+                    || fieldDef.AutoIncrement)
+                    continue; // added
 
                 var value = fieldDef.GetValue(item);
                 if (excludeDefaults
                     && (value == null || (!fieldDef.IsNullable && value.Equals(value.GetType().GetDefaultValue()))))
                     continue;
 
-                fieldDef.GetQuotedValue(item, DialectProvider);
+                fieldDef.GetQuotedValue(item, dialectProvider);
 
-                if (setFields.Length > 0) 
+                if (setFields.Length > 0)
                     setFields.Append(", ");
 
                 setFields
-                    .Append(DialectProvider.GetQuotedColumnName(fieldDef.FieldName))
+                    .Append(dialectProvider.GetQuotedColumnName(fieldDef.FieldName))
                     .Append("=")
-                    .Append(DialectProvider.GetQuotedValue(value, fieldDef.FieldType));
+                    .Append(dialectProvider.GetQuotedValue(value, fieldDef.FieldType));
             }
 
             if (setFields.Length == 0)
                 throw new ArgumentException("No non-null or non-default values were provided for type: " + typeof(T).Name);
 
             return string.Format("UPDATE {0} SET {1} {2}",
-                base.DialectProvider.GetQuotedTableName(ModelDef), setFields, WhereExpression);
+                dialectProvider.GetQuotedTableName(modelDef), setFields, q.WhereExpression);
         }
-
-	    public override string GetSubstringSql(object quotedColumn, int startIndex, int? length = null)
-	    {
-            return length != null
-                ? string.Format("substring({0}, {1}, {2})", quotedColumn, startIndex, length.Value)
-                : string.Format("substring({0}, {1}, LEN({0}) - {1} + 1)", quotedColumn, startIndex );
-        }
-
-	    public override SqlExpression<T> OrderByRandom()
-	    {
-	        return base.OrderBy("NEWID()");
-	    }
-	}
+    }
 }

src/ServiceStack.OrmLite.SqlServer/SqlServerOrmLiteDialectProvider.cs

@@ -108,7 +108,9 @@ public void EnsureUtc(bool shouldEnsureUtc)
 
         public override SqlExpression<T> SqlExpression<T>()
         {
-            return new SqlServerExpression<T>(this);
+            return !OrmLiteConfig.UseParameterizeSqlExpressions
+                ? new SqlServerExpression<T>(this)
+                : (SqlExpression<T>)new SqlServerParameterizedSqlExpression<T>(this);
         }
 
         public override bool DoesTableExist(IDbCommand dbCmd, string tableName, string schema = null)

src/ServiceStack.OrmLite/Expressions/SqlExpression.cs

@@ -1310,7 +1310,7 @@ protected virtual object VisitNewArray(NewArrayExpression na)
             return sb.ToString();
         }
 
-        protected virtual List<Object> VisitNewArrayFromExpressionList(NewArrayExpression na)
+        protected virtual List<object> VisitNewArrayFromExpressionList(NewArrayExpression na)
         {
             var exprs = VisitExpressionList(na.Expressions);
             return exprs;

src/ServiceStack.OrmLite/OrmLiteConfig.cs

@@ -190,7 +190,7 @@ public static IOrmLiteExecFilter ExecFilter
             (fieldName ?? "").Replace(" ", "");
 
         /// <summary>
-        /// Only supported in Oracle DialectProvider
+        /// Only used in Oracle or SqlServer DialectProvider
         /// </summary>
         public static bool UseParameterizeSqlExpressions { get; set; }