using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Configuration;
using System.Data.SQLite;
namespace DAL
{
internal abstract class DbHelperSQLite
{
public static string connectionString = "Data Source=" + AppDomain.CurrentDomain.BaseDirectory + @"dataleaf.db;Version=3;";
public DbHelperSQLite()
{
}
#region 公用方法
public static int GetMaxID(string FieldName, string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = GetSingle(strsql);
if (obj == null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
public static bool Exists(string strSql)
{
object obj = GetSingle(strSql);
int cmdresult;
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
public static bool Exists(string strSql, params SQLiteParameter[] cmdParms)
{
object obj = GetSingle(strSql, cmdParms);
int cmdresult;
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
#endregion
#region 执行简单SQL语句
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
using (SQLiteCommand cmd
= new SQLiteCommand
(SQLString, connection
)) {
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
connection.Close();
throw new Exception
(E
.Message); }
}
}
}
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">多条SQL语句</param>
public static void ExecuteSqlTran(ArrayList SQLStringList)
{
using (SQLiteConnection conn
= new SQLiteConnection
(connectionString
)) {
conn.Open();
SQLiteCommand cmd
= new SQLiteCommand
(); cmd.Connection = conn;
SQLiteTransaction tx = conn.BeginTransaction();
cmd.Transaction = tx;
try
{
for (int n = 0; n < SQLStringList.Count; n++)
{
string strsql = SQLStringList[n].ToString();
if (strsql.Trim().Length > 1)
{
cmd.CommandText = strsql;
cmd.ExecuteNonQuery();
}
}
tx.Commit();
}
catch (System.Data.SQLite.SQLiteException E)
{
tx.Rollback();
throw new Exception
(E
.Message); }
}
}
/// <summary>
/// 执行带一个存储过程参数的的SQL语句。
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, string content)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
SQLiteCommand cmd
= new SQLiteCommand
(SQLString, connection
); SQLiteParameter myParameter
= new SQLiteParameter
("@content", DbType
.String); myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
throw new Exception
(E
.Message); }
finally
{
cmd.Dispose();
connection.Close();
}
}
}
/// <summary>
/// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
/// </summary>
/// <param name="strSQL">SQL语句</param>
/// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
SQLiteCommand cmd
= new SQLiteCommand
(strSQL, connection
); SQLiteParameter myParameter
= new SQLiteParameter
("@fs", DbType
.Binary); myParameter.Value = fs;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
throw new Exception
(E
.Message); }
finally
{
cmd.Dispose();
connection.Close();
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
using (SQLiteCommand cmd
= new SQLiteCommand
(SQLString, connection
)) {
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SQLite.SQLiteException e)
{
connection.Close();
throw new Exception
(e
.Message); }
}
}
}
/// <summary>
/// 执行查询语句，返回SQLiteDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>SQLiteDataReader</returns>
public static SQLiteDataReader ExecuteReader(string strSQL)
{
SQLiteConnection connection
= new SQLiteConnection
(connectionString
); SQLiteCommand cmd
= new SQLiteCommand
(strSQL, connection
); try
{
connection.Open();
SQLiteDataReader myReader = cmd.ExecuteReader();
return myReader;
}
catch (System.Data.SQLite.SQLiteException e)
{
throw new Exception
(e
.Message); }
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
DataSet ds
= new DataSet
(); try
{
connection.Open();
SQLiteDataAdapter command
= new SQLiteDataAdapter
(SQLString, connection
); command.Fill(ds, "ds");
}
catch (System.Data.SQLite.SQLiteException ex)
{
throw new Exception
(ex
.Message); }
return ds;
}
}
#endregion
#region 执行带参数的SQL语句
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
using (SQLiteCommand cmd
= new SQLiteCommand
()) {
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
int rows = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
throw new Exception
(E
.Message); }
}
}
}
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SQLiteParameter[]）</param>
public static void ExecuteSqlTran(Hashtable SQLStringList)
{
using (SQLiteConnection conn
= new SQLiteConnection
(connectionString
)) {
conn.Open();
using (SQLiteTransaction trans = conn.BeginTransaction())
{
SQLiteCommand cmd
= new SQLiteCommand
(); try
{
//循环
foreach (DictionaryEntry myDE in SQLStringList)
{
string cmdText = myDE.Key.ToString();
SQLiteParameter[] cmdParms = (SQLiteParameter[])myDE.Value;
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
trans.Commit();
}
}
catch
{
trans.Rollback();
throw;
}
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
using (SQLiteCommand cmd
= new SQLiteCommand
()) {
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
object obj = cmd.ExecuteScalar();
cmd.Parameters.Clear();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SQLite.SQLiteException e)
{
throw new Exception
(e
.Message); }
}
}
}
/// <summary>
/// 执行查询语句，返回SQLiteDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>SQLiteDataReader</returns>
public static SQLiteDataReader ExecuteReader(string SQLString, params SQLiteParameter[] cmdParms)
{
SQLiteConnection connection
= new SQLiteConnection
(connectionString
); SQLiteCommand cmd
= new SQLiteCommand
(); try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
SQLiteDataReader myReader = cmd.ExecuteReader();
cmd.Parameters.Clear();
return myReader;
}
catch (System.Data.SQLite.SQLiteException e)
{
throw new Exception
(e
.Message); }
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection
= new SQLiteConnection
(connectionString
)) {
SQLiteCommand cmd
= new SQLiteCommand
(); PrepareCommand(cmd, connection, null, SQLString, cmdParms);
using (SQLiteDataAdapter da
= new SQLiteDataAdapter
(cmd
)) {
DataSet ds
= new DataSet
(); try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (System.Data.SQLite.SQLiteException ex)
{
throw new Exception
(ex
.Message); }
return ds;
}
}
}
private static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn, SQLiteTransaction trans, string cmdText, SQLiteParameter[] cmdParms)
{
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = CommandType.Text;//cmdType;
if (cmdParms != null)
{
foreach (SQLiteParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
#endregion
}
}
//csharp/6835