using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Data.OleDb;
using System.IO;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Threading;
using System.Web;
using NewLife;
using NewLife.Compression;
using NewLife.Configuration;
using NewLife.Reflection;
using NewLife.Web;
namespace XCode.DataAccessLayer
{
/// <summary>数据库基类</summary>
/// <remarks>
/// 数据库类的职责是抽象不同数据库的共同点，理应最小化，保证原汁原味，因此不做缓存等实现。
/// 对于每一个连接字符串配置，都有一个数据库实例，而不是每个数据库类型一个实例，因为同类型数据库不同版本行为不同。
/// </remarks>
abstract class DbBase : DisposeBase, IDatabase
{
#region 构造函数
/// <summary>销毁资源时，回滚未提交事务，并关闭数据库连接</summary>
/// <param name="disposing"></param>
protected override void OnDispose(bool disposing)
{
base.OnDispose(disposing);
//if (_sessions != null)
//{
// // 销毁本线程的数据库会话，似乎无法销毁别的线程的数据库会话
// if (_sessions.ContainsKey(this)) _sessions.Remove(this);
//}
if (_sessions != null) ReleaseSession();
if (_metadata != null)
{
// 销毁本数据库的元数据对象
try
{
_metadata.Dispose();
}
catch { }
_metadata = null;
}
}
/// <summary>释放所有会话</summary>
internal void ReleaseSession()
{
if (_sessions != null)
{
// 销毁本数据库的所有数据库会话
lock (_sessions)
{
foreach (var session in _sessions.Values)
{
try
{
session.Dispose();
}
catch { }
}
_sessions.Clear();
_sessions = null;
}
}
}
#endregion
#region 常量
protected static class _
{
public static readonly String DataSource = "Data Source";
}
#endregion
#region 属性
/// <summary>返回数据库类型。外部DAL数据库类请使用Other</summary>
public virtual DatabaseType DbType { get { return DatabaseType.Other; } }
/// <summary>工厂</summary>
public virtual DbProviderFactory Factory { get { return OleDbFactory.Instance; } }
private String _ConnName;
/// <summary>连接名</summary>
public String ConnName { get { return _ConnName; } set { _ConnName = value; } }
private String _ConnectionString;
/// <summary>链接字符串</summary>
public virtual String ConnectionString
{
get
{
if (_ConnectionString == null) _ConnectionString = DefaultConnectionString;
return _ConnectionString;
}
set
{
XDbConnectionStringBuilder builder = new XDbConnectionStringBuilder();
builder.ConnectionString = value;
OnSetConnectionString(builder);
_ConnectionString = builder.ConnectionString;
ReleaseSession();
}
}
protected virtual String DefaultConnectionString { get { return String.Empty; } }
const String KEY_OWNER = "Owner";
/// <summary>设置连接字符串时允许从中取值或修改，基类用于读取拥有者Owner，子类重写时应调用基类</summary>
/// <param name="builder"></param>
protected virtual void OnSetConnectionString(XDbConnectionStringBuilder builder)
{
String value;
if (builder.TryGetAndRemove(KEY_OWNER, out value) && !String.IsNullOrEmpty(value)) Owner = value;
}
private String _Owner;
/// <summary>拥有者</summary>
public virtual String Owner { get { return _Owner; } set { _Owner = value; } }
private String _ServerVersion;
/// <summary>数据库服务器版本</summary>
public virtual String ServerVersion
{
get
{
if (_ServerVersion != null) return _ServerVersion;
_ServerVersion = String.Empty;
IDbSession session = CreateSession();
if (!session.Opened) session.Open();
try
{
_ServerVersion = session.Conn.ServerVersion;
return _ServerVersion;
}
finally { session.AutoClose(); }
}
}
#endregion
#region 方法
/// <summary>保证数据库在每一个线程都有唯一的一个实例</summary>
private Dictionary<Int32, IDbSession> _sessions;
///// <summary>
///// 保存当前数据库的所有会话
///// </summary>
//private List<IDbSession> _MySessions;
/// <summary>创建数据库会话，数据库在每一个线程都有唯一的一个实例</summary>
/// <returns></returns>
public IDbSession CreateSession()
{
if (_sessions == null) _sessions = new Dictionary<Int32, IDbSession>();
var tid = Thread.CurrentThread.ManagedThreadId;
IDbSession session = null;
// 会话可能已经被销毁
if (_sessions.TryGetValue(tid, out session) && !session.Disposed) return session;
lock (_sessions)
{
if (_sessions.TryGetValue(tid, out session) && !session.Disposed) return session;
//if (_MySessions == null) _MySessions = new List<IDbSession>();
//if (session != null && _MySessions.Contains(session)) _MySessions.Remove(session);
session = OnCreateSession();
session.ConnectionString = ConnectionString;
if (session is DbSession) (session as DbSession).Database = this;
_sessions[tid] = session;
//_MySessions.Add(session);
return session;
}
}
/// <summary>创建数据库会话</summary>
/// <returns></returns>
protected abstract IDbSession OnCreateSession();
/// <summary>唯一实例</summary>
private IMetaData _metadata;
/// <summary>创建元数据对象，唯一实例</summary>
/// <returns></returns>
public IMetaData CreateMetaData()
{
if (_metadata != null && !_metadata.Disposed) return _metadata;
_metadata = OnCreateMetaData();
if (_metadata is DbMetaData) (_metadata as DbMetaData).Database = this;
return _metadata;
}
/// <summary>创建元数据对象</summary>
/// <returns></returns>
protected abstract IMetaData OnCreateMetaData();
/// <summary>获取提供者工厂</summary>
/// <param name="assemblyFile"></param>
/// <param name="className"></param>
/// <returns></returns>
protected static DbProviderFactory GetProviderFactory(String assemblyFile, String className)
{
//反射实现获取数据库工厂
String file = assemblyFile;
if (!Runtime.IsWeb)
file = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, file);
else
file = Path.Combine(HttpRuntime.BinDirectory, file);
if (!File.Exists(file))
{
CheckAndDownload(file);
// 如果还没有，就写异常
if (!File.Exists(file)) throw new FileNotFoundException("缺少文件" + file + "！", file);
}
Assembly asm = Assembly.LoadFile(file);
if (asm == null) return null;
Type type = asm.GetType(className);
if (type == null) return null;
var field = FieldInfoX.Create(type, "Instance");
if (field == null) return Activator.CreateInstance(type) as DbProviderFactory;
return field.GetValue(null) as DbProviderFactory;
}
protected static void CheckAndDownload(String file, String targetPath = null)
{
if (!Path.IsPathRooted(file))
{
if (!Runtime.IsWeb)
file = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, file);
else
file = Path.Combine(HttpRuntime.BinDirectory, file);
}
if (File.Exists(file) && new FileInfo(file).Length > 0) return;
// 目标目录
String dir = !String.IsNullOrEmpty(targetPath) ? targetPath : Path.GetDirectoryName(file);
// 从网上下载文件
var zipfile = Path.GetFileNameWithoutExtension(file);
try
{
#region 检测64位平台
Module module = typeof(Object).Module;
PortableExecutableKinds kind;
ImageFileMachine machine;
module.GetPEKind(out kind, out machine);
if (machine != ImageFileMachine.I386) zipfile += "64";
#endregion
zipfile += ".zip";
String url = String.Format(ServiceAddress, zipfile);
// 目标Zip文件
zipfile = Path.Combine(dir, zipfile);
// Zip文件不存在，准备下载
if (!File.Exists(zipfile) || new FileInfo(zipfile).Length <= 0)
{
DAL.WriteLog("准备从{0}下载文件到{1}！", url, zipfile);
var client = new WebClientX(true, true);
// 同步下载，3秒超时
client.Timeout = 3000;
//var data = client.DownloadData(url);
if (!Directory.Exists(dir)) Directory.CreateDirectory(dir);
client.DownloadFile(url, zipfile);
client.Dispose();
}
DAL.WriteLog("下载完成，准备解压到{0}！", dir);
//var ms = new MemoryStream(data);
//if (file.EndsWith("64")) file = file.Substring(0, file.Length - 2);
//IOHelper.DecompressFile(ms, dir, file, false);
ZipFile.Extract(zipfile, dir, true);
DAL.WriteLog("解压完成！");
}
catch (ZipException ex)
{
if (File.Exists(zipfile)) File.Delete(zipfile);
DAL.WriteLog("解压失败，删除压缩文件！{0}", ex.ToString());
}
catch (Exception ex)
{
DAL.WriteLog(ex.ToString());
}
}
static String _ServiceAddress;
static String ServiceAddress
{
get
{
if (_ServiceAddress == null) _ServiceAddress = Config.GetConfig<String>("", "http://j.nnhy.org/?id=3&f={0}");
return _ServiceAddress;
}
}
/// <summary>是否支持该提供者所描述的数据库</summary>
/// <param name="providerName">提供者</param>
/// <returns></returns>
public virtual Boolean Support(String providerName) { return !String.IsNullOrEmpty(providerName) && providerName.ToLower().Contains(this.DbType.ToString().ToLower()); }
#endregion
#region 分页
/// <summary>构造分页SQL，优先选择max/min，然后选择not in</summary>
/// <remarks>
/// 两个构造分页SQL的方法，区别就在于查询生成器能够构造出来更好的分页语句，尽可能的避免子查询。
/// MS体系的分页精髓就在于唯一键，当唯一键带有Asc/Desc/Unkown等排序结尾时，就采用最大最小值分页，否则使用较次的TopNotIn分页。
/// TopNotIn分页和MaxMin分页的弊端就在于无法完美的支持GroupBy查询分页，只能查到第一页，往后分页就不行了，因为没有主键。
/// </remarks>
/// <param name="sql">SQL语句</param>
/// <param name="startRowIndex">开始行，0表示第一行</param>
/// <param name="maximumRows">最大返回行数，0表示所有行</param>
/// <param name="keyColumn">唯一键。用于not in分页</param>
/// <returns>分页SQL</returns>
public virtual String PageSplit(String sql, Int32 startRowIndex, Int32 maximumRows, String keyColumn)
{
// 从第一行开始，不需要分页
if (startRowIndex <= 0 && maximumRows < 1) return sql;
#region Max/Min分页
// 如果要使用max/min分页法，首先keyColumn必须有asc或者desc
if (!String.IsNullOrEmpty(keyColumn))
{
String kc = keyColumn.ToLower();
if (kc.EndsWith(" desc") || kc.EndsWith(" asc") || kc.EndsWith(" unknown"))
{
String str = PageSplitMaxMin(sql, startRowIndex, maximumRows, keyColumn);
if (!String.IsNullOrEmpty(str)) return str;
// 如果不能使用最大最小值分页，则砍掉排序，为TopNotIn分页做准备
keyColumn = keyColumn.Substring(0, keyColumn.IndexOf(" "));
}
}
#endregion
//检查简单SQL。为了让生成分页SQL更短
String tablename = CheckSimpleSQL(sql);
if (tablename != sql)
sql = tablename;
else
sql = String.Format("({0}) XCode_Temp_a", sql);
// 取第一页也不用分页。把这代码放到这里，主要是数字分页中要自己处理这种情况
if (startRowIndex <= 0 && maximumRows > 0)
return String.Format("Select Top {0} * From {1}", maximumRows, sql);
if (String.IsNullOrEmpty(keyColumn)) throw new ArgumentNullException("keyColumn", "这里用的not in分页算法要求指定主键列！");
if (maximumRows < 1)
sql = String.Format("Select * From {1} Where {2} Not In(Select Top {0} {2} From {1})", startRowIndex, sql, keyColumn);
else
sql = String.Format("Select Top {0} * From {1} Where {2} Not In(Select Top {3} {2} From {1})", maximumRows, sql, keyColumn, startRowIndex);
return sql;
}
/// <summary>按唯一数字最大最小分析</summary>
/// <param name="sql">SQL语句</param>
/// <param name="startRowIndex">开始行，0表示第一行</param>
/// <param name="maximumRows">最大返回行数，0表示所有行</param>
/// <param name="keyColumn">唯一键。用于not in分页</param>
/// <returns>分页SQL</returns>
public static String PageSplitMaxMin(String sql, Int32 startRowIndex, Int32 maximumRows, String keyColumn)
{
// 唯一键的顺序。默认为Empty，可以为asc或desc，如果有，则表明主键列是数字唯一列，可以使用max/min分页法
Boolean isAscOrder = keyColumn.ToLower().EndsWith(" asc");
// 是否使用max/min分页法
Boolean canMaxMin = false;
// 如果sql最外层有排序，且唯一的一个排序字段就是keyColumn时，可用max/min分页法
// 如果sql最外层没有排序，其排序不是unknown，可用max/min分页法
MatchCollection ms = reg_Order.Matches(sql);
if (ms != null && ms.Count > 0 && ms[0].Index > 0)
{
#region 有OrderBy
// 取第一页也不用分页。把这代码放到这里，主要是数字分页中要自己处理这种情况
if (startRowIndex <= 0 && maximumRows > 0)
return String.Format("Select Top {0} * From {1}", maximumRows, CheckSimpleSQL(sql));
keyColumn = keyColumn.Substring(0, keyColumn.IndexOf(" "));
sql = sql.Substring(0, ms[0].Index);
String strOrderBy = ms[0].Groups[1].Value.Trim();
// 只有一个排序字段
if (!String.IsNullOrEmpty(strOrderBy) && !strOrderBy.Contains(","))
{
// 有asc或者desc。没有时，默认为asc
if (strOrderBy.ToLower().EndsWith(" desc"))
{
String str = strOrderBy.Substring(0, strOrderBy.Length - " desc".Length).Trim();
// 排序字段等于keyColumn
if (str.ToLower() == keyColumn.ToLower())
{
isAscOrder = false;
canMaxMin = true;
}
}
else if (strOrderBy.ToLower().EndsWith(" asc"))
{
String str = strOrderBy.Substring(0, strOrderBy.Length - " asc".Length).Trim();
// 排序字段等于keyColumn
if (str.ToLower() == keyColumn.ToLower())
{
isAscOrder = true;
canMaxMin = true;
}
}
else if (!strOrderBy.Contains(" ")) // 不含空格，是唯一排序字段
{
// 排序字段等于keyColumn
if (strOrderBy.ToLower() == keyColumn.ToLower())
{
isAscOrder = true;
canMaxMin = true;
}
}
}
#endregion
}
else
{
// 取第一页也不用分页。把这代码放到这里，主要是数字分页中要自己处理这种情况
if (startRowIndex <= 0 && maximumRows > 0)
{
//数字分页中，业务上一般使用降序，Entity类会给keyColumn指定降序的
//但是，在第一页的时候，没有用到keyColumn，而数据库一般默认是升序
//这时候就会出现第一页是升序，后面页是降序的情况了。这里改正这个BUG
if (keyColumn.ToLower().EndsWith(" desc") || keyColumn.ToLower().EndsWith(" asc"))
return String.Format("Select Top {0} * From {1} Order By {2}", maximumRows, CheckSimpleSQL(sql), keyColumn);
else
return String.Format("Select Top {0} * From {1}", maximumRows, CheckSimpleSQL(sql));
}
if (!keyColumn.ToLower().EndsWith(" unknown")) canMaxMin = true;
keyColumn = keyColumn.Substring(0, keyColumn.IndexOf(" "));
}
if (canMaxMin)
{
if (maximumRows < 1)
sql = String.Format("Select * From {1} Where {2}{3}(Select {4}({2}) From (Select Top {0} {2} From {1} Order By {2} {5}) XCode_Temp_a) Order By {2} {5}", startRowIndex, CheckSimpleSQL(sql), keyColumn, isAscOrder ? ">" : "<", isAscOrder ? "max" : "min", isAscOrder ? "Asc" : "Desc");
else
sql = String.Format("Select Top {0} * From {1} Where {2}{4}(Select {5}({2}) From (Select Top {3} {2} From {1} Order By {2} {6}) XCode_Temp_a) Order By {2} {6}", maximumRows, CheckSimpleSQL(sql), keyColumn, startRowIndex, isAscOrder ? ">" : "<", isAscOrder ? "max" : "min", isAscOrder ? "Asc" : "Desc");
return sql;
}
return null;
}
private static Regex reg_SimpleSQL = new Regex(@"^\s*select\s+\*\s+from\s+([\w\[\]\""\""\']+)\s*$", RegexOptions.Compiled | RegexOptions.IgnoreCase);
/// <summary>检查简单SQL语句，比如Select * From table</summary>
/// <param name="sql">待检查SQL语句</param>
/// <returns>如果是简单SQL语句则返回表名，否则返回子查询(sql) XCode_Temp_a</returns>
internal protected static String CheckSimpleSQL(String sql)
{
if (String.IsNullOrEmpty(sql)) return sql;
MatchCollection ms = reg_SimpleSQL.Matches(sql);
if (ms == null || ms.Count < 1 || ms[0].Groups.Count < 2 ||
String.IsNullOrEmpty(ms[0].Groups[1].Value)) return String.Format("({0}) XCode_Temp_a", sql);
return ms[0].Groups[1].Value;
}
private static Regex reg_Order = new Regex(@"\border\s*by\b([^)]+)$", RegexOptions.Compiled | RegexOptions.IgnoreCase);
/// <summary>检查是否以Order子句结尾，如果是，分割sql为前后两部分</summary>
/// <param name="sql"></param>
/// <returns></returns>
internal protected static String CheckOrderClause(ref String sql)
{
if (!sql.ToLower().Contains("order")) return null;
// 使用正则进行严格判断。必须包含Order By，并且它右边没有右括号)，表明有order by，且不是子查询的，才需要特殊处理
MatchCollection ms = reg_Order.Matches(sql);
if (ms == null || ms.Count < 1 || ms[0].Index < 1) return null;
String orderBy = sql.Substring(ms[0].Index).Trim();
sql = sql.Substring(0, ms[0].Index).Trim();
return orderBy;
}
/// <summary>构造分页SQL</summary>
/// <remarks>
/// 两个构造分页SQL的方法，区别就在于查询生成器能够构造出来更好的分页语句，尽可能的避免子查询。
/// MS体系的分页精髓就在于唯一键，当唯一键带有Asc/Desc/Unkown等排序结尾时，就采用最大最小值分页，否则使用较次的TopNotIn分页。
/// TopNotIn分页和MaxMin分页的弊端就在于无法完美的支持GroupBy查询分页，只能查到第一页，往后分页就不行了，因为没有主键。
/// </remarks>
/// <param name="builder">查询生成器</param>
/// <param name="startRowIndex">开始行，0表示第一行</param>
/// <param name="maximumRows">最大返回行数，0表示所有行</param>
/// <returns>分页SQL</returns>
public virtual SelectBuilder PageSplit(SelectBuilder builder, Int32 startRowIndex, Int32 maximumRows)
{
// 从第一行开始，不需要分页
if (startRowIndex <= 0 && maximumRows < 1) return builder;
var sql = PageSplit(builder.ToString(), startRowIndex, maximumRows, builder.Key);
var sb = new SelectBuilder();
sb.Parse(sql);
return sb;
}
#endregion
#region 数据库特性
/// <summary>当前时间函数</summary>
public virtual String DateTimeNow { get { return null; } }
/// <summary>最小时间</summary>
public virtual DateTime DateTimeMin { get { return DateTime.MinValue; } }
/// <summary>长文本长度</summary>
public virtual Int32 LongTextLength { get { return 4000; } }
/// <summary>获取Guid的函数</summary>
public virtual String NewGuid { get { return "newid()"; } }
///// <summary>
///// 保留字字符串，其实可以在首次使用时动态从Schema中加载
///// </summary>
//protected virtual String ReservedWordsStr { get { return null; } }
//private Dictionary<String, Boolean> _ReservedWords = null;
///// <summary>
///// 保留字
///// </summary>
//private Dictionary<String, Boolean> ReservedWords
//{
// get
// {
// if (_ReservedWords == null)
// {
// _ReservedWords = new Dictionary<String, Boolean>(StringComparer.OrdinalIgnoreCase);
// String[] ss = (ReservedWordsStr + "").Split(',');
// foreach (String item in ss)
// {
// String key = item.Trim();
// if (!_ReservedWords.ContainsKey(key)) _ReservedWords.Add(key, true);
// }
// }
// return _ReservedWords;
// }
//}
///// <summary>
///// 是否保留字
///// </summary>
///// <param name="word"></param>
///// <returns></returns>
//private Boolean IsReservedWord(String word) { return String.IsNullOrEmpty(word) ? false : ReservedWords.ContainsKey(word); }
/// <summary>格式化时间为SQL字符串</summary>
/// <param name="dateTime">时间值</param>
/// <returns></returns>
public virtual String FormatDateTime(DateTime dateTime) { return String.Format("'{0:yyyy-MM-dd HH:mm:ss}'", dateTime); }
/// <summary>格式化关键字</summary>
/// <param name="keyWord">表名</param>
/// <returns></returns>
public virtual String FormatKeyWord(String keyWord) { return keyWord; }
/// <summary>格式化名称，如果是关键字，则格式化后返回，否则原样返回</summary>
/// <param name="name">名称</param>
/// <returns></returns>
public virtual String FormatName(String name)
{
if (String.IsNullOrEmpty(name)) return name;
//if (CreateMetaData().ReservedWords.Contains(name)) return FormatKeyWord(name);
DbMetaData md = CreateMetaData() as DbMetaData;
if (md != null && md.ReservedWords.Contains(name)) return FormatKeyWord(name);
return name;
}
/// <summary>格式化数据为SQL数据</summary>
/// <param name="field"></param>
/// <param name="value"></param>
/// <returns></returns>
public virtual String FormatValue(IDataColumn field, Object value)
{
Boolean isNullable = true;
Type type = null;
if (field != null)
{
type = field.DataType;
isNullable = field.Nullable;
}
else if (value != null)
type = value.GetType();
TypeCode code = Type.GetTypeCode(type);
if (code == TypeCode.String)
{
if (value == null) return isNullable ? "null" : "''";
//!!! 为SQL格式化数值时，如果字符串是Empty，将不再格式化为null
//if (String.IsNullOrEmpty(value.ToString()) && isNullable) return "null";
return "'" + value.ToString().Replace("'", "''") + "'";
}
else if (code == TypeCode.DateTime)
{
if (value == null) return isNullable ? "null" : "''";
DateTime dt = Convert.ToDateTime(value);
if (dt < DateTimeMin || dt > DateTime.MaxValue) return isNullable ? "null" : "''";
if ((dt == DateTime.MinValue || dt == DateTimeMin) && isNullable) return "null";
return FormatDateTime(dt);
}
else if (code == TypeCode.Boolean)
{
if (value == null) return isNullable ? "null" : "";
return Convert.ToBoolean(value) ? "1" : "0";
}
else if (type == typeof(Byte[]))
{
Byte[] bts = (Byte[])value;
if (bts == null || bts.Length < 1) return isNullable ? "null" : "0x0";
return "0x" + BitConverter.ToString(bts).Replace("-", null);
}
else if (field.DataType == typeof(Guid))
{
if (value == null) return isNullable ? "null" : "''";
return String.Format("'{0}'", value);
}
else
{
if (value == null) return isNullable ? "null" : "";
// 转为目标类型，比如枚举转为数字
value = TypeX.ChangeType(value, type);
if (value == null) return isNullable ? "null" : "";
return value.ToString();
}
}
/// <summary>格式化标识列，返回插入数据时所用的表达式，如果字段本身支持自增，则返回空</summary>
/// <param name="field"></param>
/// <param name="value"></param>
/// <returns></returns>
public virtual String FormatIdentity(IDataColumn field, Object value) { return null; }
/// <summary>格式化参数名</summary>
/// <param name="name"></param>
/// <returns></returns>
public virtual String FormatParameterName(String name)
{
if (String.IsNullOrEmpty(name)) return name;
//DbMetaData md = CreateMetaData() as DbMetaData;
//if (md != null) name = md.ParamPrefix + name;
//return name;
return ParamPrefix + name;
}
internal protected virtual String ParamPrefix { get { return "@"; } }
/// <summary>是否Unicode编码。只是固定判断n开头的几个常见类型为Unicode编码，这种方法不是很严谨，可以考虑读取DataTypes架构</summary>
/// <param name="rawType"></param>
/// <returns></returns>
internal protected virtual Boolean IsUnicode(String rawType)
{
if (String.IsNullOrEmpty(rawType)) return false;
rawType = rawType.ToLower();
if (rawType.StartsWith("nchar") || rawType.StartsWith("nvarchar") || rawType.StartsWith("ntext") || rawType.StartsWith("nclob")) return true;
return false;
}
/// <summary>字符串相加</summary>
/// <param name="left"></param>
/// <param name="right"></param>
/// <returns></returns>
public virtual String StringConcat(String left, String right) { return (!String.IsNullOrEmpty(left) ? left : "\'\'") + "+" + (!String.IsNullOrEmpty(right) ? right : "\'\'"); }
#endregion
#region 辅助函数
/// <summary>已重载。</summary>
/// <returns></returns>
public override string ToString()
{
return String.Format("[{0}] {1} {2}", ConnName, DbType, ServerVersion);
}
protected static String ResolveFile(String file)
{
if (String.IsNullOrEmpty(file)) return file;
if (file.StartsWith("~/") || file.StartsWith("~\\"))
{
file = file.Replace("/", "\\").Replace("~\\", AppDomain.CurrentDomain.BaseDirectory.TrimEnd('\\') + "\\");
}
else if (file.StartsWith("./") || file.StartsWith(".\\"))
{
file = file.Replace("/", "\\").Replace(".\\", AppDomain.CurrentDomain.BaseDirectory.TrimEnd('\\') + "\\");
}
else if (!Path.IsPathRooted(file))
{
file = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, file.Replace("/", "\\"));
}
// 过滤掉不必要的符号
file = new FileInfo(file).FullName;
return file;
}
#endregion
}
}
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