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using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Text;
namespace Apewer.Source
{
/// <summary></summary>
abstract class DbClient
{
/// <summary></summary>
public virtual Logger Logger { get; set; }
#region Connection
DbConnection _conn = null;
string _str = null;
/// <summary></summary>
public Timeout Timeout { get; set; }
/// <summary></summary>
public DbConnection Connection { get => _conn; }
/// <summary></summary>
public bool Online { get => _conn == null ? false : (_conn.State == ConnectionState.Open); }
/// <summary>连接字符串。</summary>
public string ConnectionString { get => _str; }
/// <summary></summary>
public virtual string Connect()
{
if (_conn == null)
{
_str = GetConnectionString();
_conn = NewConnection();
_conn.ConnectionString = _str;
}
else
{
if (_conn.State == ConnectionState.Open) return null;
}
try
{
_conn.Open();
switch (_conn.State)
{
case ConnectionState.Open: return null;
default: return $"连接失败,当前处于 {_conn.State} 状态。";
}
}
catch (Exception ex)
{
Logger.Error(this, "Connect", ex, _conn.ConnectionString);
Close();
return ex.Message;
}
}
/// <summary></summary>
public void Close()
{
if (_conn != null)
{
if (_transaction != null)
{
if (_autocommit) Commit();
else Rollback();
}
_conn.Close();
_conn.Dispose();
_conn = null;
}
}
/// <summary></summary>
public void Dispose() { Close(); }
#endregion
#region Transaction
private DbTransaction _transaction = null;
private bool _autocommit = false;
/// <summary>启动事务。</summary>
public string Begin(bool commit = true) => Begin(commit, null);
/// <summary>启动事务。</summary>
public string Begin(bool commit, Class<System.Data.IsolationLevel> isolation)
{
if (Connect() != null) return "未连接。";
if (_transaction != null) return "存在已启动的事务,无法再次启动。";
try
{
_transaction = isolation ? _conn.BeginTransaction(isolation.Value) : _conn.BeginTransaction();
_autocommit = commit;
return null;
}
catch (Exception ex)
{
Logger.Error(this, "Commit", ex.Message());
return ex.Message();
}
}
/// <summary>提交事务。</summary>
public string Commit()
{
if (_transaction == null) return "事务不存在。";
try
{
_transaction.Commit();
RuntimeUtility.Dispose(_transaction);
_transaction = null;
return null;
}
catch (Exception ex)
{
RuntimeUtility.Dispose(_transaction);
_transaction = null;
Logger.Error(this, "Commit", ex.Message());
return ex.Message();
}
}
/// <summary>从挂起状态回滚事务。</summary>
public string Rollback()
{
if (_transaction == null) return "事务不存在。";
try
{
_transaction.Rollback();
RuntimeUtility.Dispose(_transaction);
_transaction = null;
return null;
}
catch (Exception ex)
{
RuntimeUtility.Dispose(_transaction);
_transaction = null;
Logger.Error(this, "Rollback", ex.Message());
return ex.Message();
}
}
#endregion
#region ADO
/// <summary>查询。</summary>
public IQuery Query(string sql) => Query(sql, null);
/// <summary>查询。</summary>
public IQuery Query(string sql, IEnumerable<IDataParameter> parameters)
{
if (TextUtility.IsBlank(sql)) return new Query(false, "语句无效。");
var connected = Connect();
if (connected.NotEmpty()) return new Query(false, connected);
try
{
using (var command = NewCommand())
{
command.Connection = _conn;
if (Timeout != null) command.CommandTimeout = Timeout.Query;
command.CommandText = sql;
if (parameters != null)
{
foreach (var parameter in parameters)
{
if (parameter != null) command.Parameters.Add(parameter);
}
}
using (var ds = new DataSet())
{
using (var da = NewDataAdapter(sql))
{
var name = "table_" + Guid.NewGuid().ToString("n");
da.Fill(ds, name);
var table = ds.Tables[name];
return new Query(table, true);
}
}
}
}
catch (Exception exception)
{
Logger.Error(this, "Query", exception, sql);
return new Query(exception);
}
}
/// <summary>执行。</summary>
public IExecute Execute(string sql) => Execute(sql, null);
/// <summary>执行单条 Transact-SQL 语句,并加入参数。</summary>
public IExecute Execute(string sql, IEnumerable<IDataParameter> parameters)
{
if (TextUtility.IsBlank(sql)) return Example.InvalidExecuteStatement;
var connected = Connect();
if (connected.NotEmpty()) return new Execute(false, connected);
var inTransaction = _transaction != null;
if (!inTransaction) Begin();
try
{
using (var command = NewCommand())
{
command.Connection = _conn;
command.Transaction = (DbTransaction)_transaction;
if (Timeout != null) command.CommandTimeout = Timeout.Execute;
command.CommandText = sql;
if (parameters != null)
{
foreach (var parameter in parameters)
{
if (parameter != null) command.Parameters.Add(parameter);
}
}
var rows = command.ExecuteNonQuery();
if (!inTransaction) Commit(); // todo 此处应该检查事务提交产生的错误。
return new Execute(true, rows);
}
}
catch (Exception exception)
{
Logger.Error(this, "Execute", exception, sql);
if (!inTransaction) Rollback();
return new Execute(exception);
}
}
#endregion
#region ORM - Query
/// <summary>查询记录。</summary>
/// <param name="model">记录模型。</param>
/// <param name="sql">SQL 语句。</param>
public Result<object[]> Query(Type model, string sql)
{
if (_conn == null) return new Result<object[]>("连接无效。");
if (model == null) return new Result<object[]>("数据模型类型无效。");
if (string.IsNullOrEmpty(sql)) return new Result<object[]>("SQL 语句无效。");
var query = Query(sql);
var result = null as Result<object[]>;
if (query.Success)
{
try
{
var array = OrmHelper.Fill(query, model);
result = new Result<object[]>(array);
}
catch (Exception ex)
{
result = new Result<object[]>(ex);
}
}
else
{
result = new Result<object[]>(query.Message);
}
query.Dispose();
return result;
}
/// <summary></summary>
public Result<T[]> Query<T>(string sql) where T : class, new()
{
var query = Query(sql);
if (!query.Success) return new Result<T[]>(query.Message);
var records = query.Fill<T>();
query.Dispose();
var result = new Result<T[]>(records);
return result;
}
#endregion
#region Static
/// <summary>对文本转义,符合 SQL 安全性。可根据字段类型限制 UTF-8 字节数,默认为 0 时不限制字节数。</summary>
protected static string Escape(string text, int bytes = 0)
{
if (text.IsEmpty()) return "";
var t = text ?? "";
t = t.Replace("\\", "\\\\");
t = t.Replace("'", "\\'");
t = t.Replace("\n", "\\n");
t = t.Replace("\r", "\\r");
t = t.Replace("\b", "\\b");
t = t.Replace("\t", "\\t");
t = t.Replace("\f", "\\f");
if (bytes > 5)
{
if (t.Bytes(Encoding.UTF8).Length > bytes)
{
while (true)
{
t = t.Substring(0, t.Length - 1);
if (t.Bytes(Encoding.UTF8).Length <= (bytes - 4)) break;
}
t = t + " ...";
}
}
return t;
}
#endregion
/// <summary></summary>
protected abstract string GetConnectionString();
/// <summary></summary>
protected abstract DbConnection NewConnection();
/// <summary></summary>
protected abstract DbDataAdapter NewDataAdapter(string sql);
/// <summary></summary>
protected abstract DbCommand NewCommand();
}
}