//******************************************************************************************************//  AmendExpressionAttribute.cs - Gbtc////  Copyright © 2017, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  02/24/2017 - J. Ritchie Carroll//       Generated original version of source code.////****************************************************************************************************** using System;using System.Diagnostics.CodeAnalysis; namespace GSF.Data.Model{    #region [ Enumerations ]     /// <summary>    /// Statement types for amendment application.    /// </summary>    [Flags]    public enum StatementTypes    {        /// <summary>        /// Apply amendment to all SELECT statements, i.e., <see cref="SelectCount"/>, <see cref="SelectSet"/> and <see cref="SelectRow"/>.        /// </summary>        Select = SelectCount | SelectSet | SelectRow,        /// <summary>        /// Apply amendment to SELECT COUNT statements.        /// </summary>        SelectCount = (int)Bits.Bit00,        /// <summary>        /// Apply amendment to SELECT statements that can return multiple rows of data.        /// </summary>        SelectSet = (int)Bits.Bit01,        /// <summary>        /// Apply amendment to SELECT statements that will return a single row of data.        /// </summary>        SelectRow = (int)Bits.Bit02,        /// <summary>        /// Apply amendment to INSERT statements.        /// </summary>        Insert = (int)Bits.Bit03,        /// <summary>        /// Apply amendment to UPDATE statements.        /// </summary>        Update = (int)Bits.Bit04,        /// <summary>        /// Apply amendment to DELETE statements.        /// </summary>        Delete = (int)Bits.Bit05    }     /// <summary>    /// Target expressions for amendment application.    /// </summary>    public enum TargetExpression    {        /// <summary>        /// Apply amendment to table name.        /// </summary>        TableName,        /// <summary>        /// Apply amendment to full field list.        /// </summary>        FieldList    }     /// <summary>    /// Locations for target expression amendment application.    /// </summary>    public enum AffixPosition    {        /// <summary>        /// Apply amendment to beginning of <see cref="TargetExpression"/>.        /// </summary>        Prefix,        /// <summary>        /// Apply amendment to ending of <see cref="TargetExpression"/>.        /// </summary>        Suffix    }     #endregion     /// <summary>    /// Defines an attribute that will request amendment of a table name or field list with the specified text.    /// </summary>    /// <remarks>    /// <para>    /// As an example, this can be used to add table hints, e.g., <c>WITH (NOLOCK)</c>, for select statements in    /// SQL Server.    /// </para>    /// <para>    /// Applying the <see cref="AmendExpressionAttribute"/> to a modeled table with no specified database type parameter    /// will be meant to infer that the amendment be used for all database types. Using a specific database type as a    /// parameter to the attribute, e.g., <c>[AmendExpression("WITH (NOLOCK)", DatabaseType.SQLServer)]</c>, means the    /// amendment text will only be applied to the specific database - however, the attribute allows multiple instances    /// on the same identifier so you could specify that amendment application only be applied to two databases:    /// <code>    /// [AmendExpression("AS T1", DatabaseType.SQLServer), AmendExpression("AS T1", DatabaseType.MySQL)]    /// </code>    /// Other parameters exist to fully customize target expression, set affix position and specify statement types:    /// <code>    /// [AmendExpression("TOP 200",    ///     TargetExpression = TargetExpression.FieldList,    ///     AffixPosition = AffixPosition.Prefix,    ///     StatementTypes = StatementTypes.SelectSet)]    /// </code>    /// </para>    /// </remarks>    [SuppressMessage("Microsoft.Design", "CA1019:DefineAccessorsForAttributeArguments")]    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]        public sealed class AmendExpressionAttribute : Attribute    {        /// <summary>        /// Gets or sets amendment text to be applied.        /// </summary>        public string AmendmentText        {            get;        }         /// <summary>        /// Gets or sets target expression for amendment application; defaults to <see cref="Model.TargetExpression.TableName"/>.        /// </summary>        public TargetExpression TargetExpression        {            get;            set;        }         /// <summary>        /// Gets or sets location for amendment application; defaults to <see cref="Model.AffixPosition.Suffix"/>.        /// </summary>        public AffixPosition AffixPosition        {            get;            set;        }         /// <summary>        /// Gets or sets statement types for amendment application; defaults to <see cref="Model.StatementTypes.Select"/>.        /// </summary>        public StatementTypes StatementTypes        {            get;            set;        }         /// <summary>        /// Gets target <see cref="DatabaseType"/> for amendment application.        /// </summary>        /// <remarks>        /// When value is <c>null</c>, amendment text will be applied to all database types.        /// </remarks>        public DatabaseType? TargetDatabaseType        {            get;        }         /// <summary>        /// Creates a new <see cref="AmendExpressionAttribute"/> that will request application of <paramref name="amendmentText"/>        /// for any database.        /// </summary>        /// <param name="amendmentText">Amendment text to apply.</param>        public AmendExpressionAttribute(string amendmentText)        {            AmendmentText = amendmentText;            TargetDatabaseType = null;            TargetExpression = TargetExpression.TableName;            AffixPosition = AffixPosition.Suffix;            StatementTypes = StatementTypes.Select;        }         /// <summary>        /// Creates a new <see cref="AmendExpressionAttribute"/> that will request application of <paramref name="amendmentText"/>        /// for the specified <paramref name="targetDatabaseType"/>.        /// </summary>        /// <param name="amendmentText">Amendment text to apply.</param>        /// <param name="targetDatabaseType">Target <see cref="DatabaseType"/> for amendment text.</param>        public AmendExpressionAttribute(string amendmentText, DatabaseType targetDatabaseType)        {            AmendmentText = amendmentText;            TargetDatabaseType = targetDatabaseType;            TargetExpression = TargetExpression.TableName;            AffixPosition = AffixPosition.Suffix;            StatementTypes = StatementTypes.Select;        }    }}