apewer-dotnet/Apewer/Source/Access.cs

using Apewer.Internals;

#if NETFX
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Text;
#endif

namespace Apewer.Source
{

    /// <summary>用于快速连接 Microsoft Access 数据库的辅助。</summary>
    public partial class Access
    {

        /// <summary>尝试解析 Access 文件的密码。</summary>
        /// <remarks>当操作系统启用随机化内存分配时，此方法可能会产生异常。</remarks>
        public static string[] ParsePassword(string path) => AccessHelper.GetPassword(path);

    }

#if NETFX

    public partial class Access : IDatabase, IDisposable
    {

        /// <summary>创建 Access 类的新实例。</summary>
        public static Access Jet4() => new Access(AccessHelper.JetOleDB4);

        /// <summary>创建 Access 类的新实例。</summary>
        public static Access Ace12() => new Access(AccessHelper.AceOleDB12);

        #region 属性、构造函数和 Dispose。

        private OleDbConnection _connection = null;

        internal string Provider { get; set; }

        /// <summary>构造函数。</summary>
        internal Access(string provider)
        {
            Provider = provider;
            Timeout = new Timeout();
        }

        /// <summary>释放资源。</summary>
        public void Dispose() => Close();

        #endregion

        #region 日志。

        /// <summary>获取或设置日志记录。</summary>
        public Logger Logger { get; set; }

        private void LogError(string action, Exception ex, string addtion)
        {
            var logger = Logger;
            if (logger != null) logger.Error(this, "Access", action, ex.GetType().FullName, ex.Message, addtion);
        }

        #endregion

        #region 连接。

        /// <summary>获取或设置数据库文件的路径。</summary>
        public string Path { get; set; }

        /// <summary>Microsoft Access System Database。</summary>
        public string Josd { get; set; }

        /// <summary>获取或设置用于连接数据库的密码。</summary>
        public string Pass { get; set; }

        /// <summary>获取或设置超时。</summary>
        public Timeout Timeout { get; set; }

        /// <summary>数据库是否已经连接。</summary>
        public bool Online
        {
            get
            {
                if (_connection != null)
                {
                    if (_connection.State == ConnectionState.Open) return true;
                }
                return false;
            }
        }

        /// <summary>连接数据库，若未连接则尝试连接。</summary>
        /// <returns>是否已连接。</returns>
        public bool Connect()
        {
            var cs = GenerateConnectionString();
            if (_connection == null)
            {
                _connection = new OleDbConnection();
                _connection.ConnectionString = cs;
            }
            else
            {
                if (_connection.State == ConnectionState.Open) return true;
            }
            try
            {
                _connection.Open();
                if (_connection.State == ConnectionState.Open) return true;
            }
            catch (Exception argException)
            {
                LogError("Connect", argException, cs);
                Close();
            }
            return false;
        }

        /// <summary>释放对象所占用的系统资源。</summary>
        public void Close()
        {
            if (_connection != null)
            {
                _connection.Close();
                _connection.Dispose();
                _connection = null;
            }
        }

        /// <summary>获取或设置连接字符串。</summary>
        private string GenerateConnectionString()
        {
            if (!File.Exists(Path)) return null;

            var sb = new StringBuilder();

            sb.Append("provider=", Provider, "; ");

            if (!string.IsNullOrEmpty(Path)) sb.Append("data source=", Path, "; ");

            if (string.IsNullOrEmpty(Pass)) sb.Append("persist security info=false; ");
            else sb.Append("jet oledb:database password=\"", Pass, "\"; ");

            // Microsoft Access Workgroup Information
            if (!string.IsNullOrEmpty(Josd)) sb.Append("jet oledb:system database=", Josd, "; ");

            return sb.ToString();
        }

        #endregion

        #region 查询和执行。

        /// <summary>使用 SQL 语句进行查询。</summary>
        public IQuery Query(string sql) => Query(sql, null);

        /// <summary>使用 SQL 语句进行查询。</summary>
        public IQuery Query(string sql, IEnumerable<IDataParameter> parameters)
        {
            if (sql.IsBlank()) return Example.InvalidQueryStatement;

            const string table = "queryresult";

            var connected = Connect();
            if (!connected) return Example.InvalidQueryConnection;

            var query = new Query();
            try
            {
                var command = new OleDbCommand();
                command.Connection = _connection;
                command.CommandTimeout = Timeout.Query;
                command.CommandText = sql;
                if (parameters != null)
                {
                    foreach (var p in parameters)
                    {
                        if (p != null) command.Parameters.Add(p);
                    }
                }
                using (var ds = new DataSet())
                {
                    using (var da = new OleDbDataAdapter(sql, _connection))
                    {
                        da.Fill(ds, table);
                        query.Table = ds.Tables[table];
                    }
                }
                command.Dispose();
                query.Success = true;
            }
            catch (Exception exception)
            {
                LogError("Query", exception, sql);
                query.Success = false;
                query.Exception = exception;
            }
            return query;
        }

        /// <summary>执行 SQL 语句。</summary>
        public IExecute Execute(string sql) => Execute(sql, null);

        /// <summary>执行 SQL 语句，并加入参数。</summary>
        public IExecute Execute(string sql, IEnumerable<IDataParameter> parameters)
        {
            if (sql.IsBlank()) return Example.InvalidExecuteStatement;

            var connected = Connect();
            if (!connected) return Example.InvalidExecuteConnection;

            var execute = new Execute();
            using (var transaction = _connection.BeginTransaction())
            {
                try
                {
                    using (var command = new OleDbCommand())
                    {
                        command.Connection = _connection;
                        command.Transaction = transaction;
                        command.CommandTimeout = Timeout.Execute;
                        command.CommandText = sql;
                        if (parameters != null)
                        {
                            foreach (var parameter in parameters)
                            {
                                if (parameter == null) continue;
                                command.Parameters.Add(parameter);
                            }
                        }
                        execute.Rows += command.ExecuteNonQuery();
                        transaction.Commit();
                    }
                    execute.Success = true;
                }
                catch (Exception exception)
                {
                    LogError("Execute", exception, sql);
                    try { transaction.Rollback(); } catch { }
                    execute.Success = false;
                    execute.Exception = exception;
                }
            }

            return execute;
        }

        #endregion

        #region Parameter

        /// <summary>创建参数列表。</summary>
        public static List<IDbDataParameter> NewParameterList()
        {
            return new List<IDbDataParameter>();
        }

        /// <summary>创建参数。</summary>
        public static IDbDataParameter CreateParameter(String field, DbType type, Int32 size, Object value)
        {
            var p = new OleDbParameter();
            p.ParameterName = field;
            p.DbType = type;
            p.Size = size;
            p.Value = value;
            return p;
        }

        /// <summary>创建参数。</summary>
        public static IDbDataParameter CreateParameter(String field, DbType type, Object value)
        {
            var p = new OleDbParameter();
            p.ParameterName = field;
            p.DbType = type;
            p.Value = value;
            return p;
        }

        #endregion

    }

    /// <summary>使用 Microsoft.Jet.OLEDB.4.0 访问 Access 97 - 2003 数据库文件。</summary>
    public class AccessJet4 : Access
    {

        /// <summary>创建 Access 类的新实例。</summary>
        public AccessJet4() : base(AccessHelper.JetOleDB4) { }

        /// <summary>创建 Access 类的新实例。</summary>
        public AccessJet4(string path) : base(AccessHelper.JetOleDB4)
        {
            Path = path;
        }

    }

    /// <summary>使用 Microsoft.ACE.OLEDB.12.0 访问 Access 2007 数据库文件。</summary>
    public class AccessAce12 : Access
    {

        /// <summary>创建 Access 类的新实例。</summary>
        public AccessAce12() : base(AccessHelper.AceOleDB12) { }

        /// <summary>创建 Access 类的新实例。</summary>
        public AccessAce12(string path) : base(AccessHelper.AceOleDB12)
        {
            Path = path;
        }

    }

#endif

}