SQLite帮助类SQlitehelper 实现对SQLite数据的增删改查

public class SQLiteHelper
{

public const string sConn = "Data Source=" + @"path";

/// <summary>
/// 查询，返回object ,得到查询结果的首行首列的值，若没有首行首列返回NUll
/// </summary>
/// <param name="sql">查询语句</param>
/// <param name="parameters">可选参数</param>
/// <returns></returns>
public static object ExecuteScalar(string sql, params SQLiteParameter[] parameters)
{
return ExecuteScalar(sql, CommandType.Text, parameters);

}

/// <summary>
/// 查询，返回object  ，执行SQl语句，得到查询结果的首行首列，若没有首行首列返回null
/// </summary>
/// <param name="sql">查询语句</param>
/// <param name="type">如何解释命令字符串</param>
/// <param name="parameters">可选的参数</param>
/// <returns></returns>
public static object ExecuteScalar(string sql, CommandType type, params SQLiteParameter[] parameters)
{
using (SQLiteConnection conn = new SQLiteConnection(sConn))
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand(sql, conn);

cmd.CommandType = type;
cmd.Parameters.AddRange(parameters);
object obj = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return obj;
}
}

/// <summary>
/// 执行增、删、改
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="parameters">可选参数</param>
/// <returns>返回int 得到受影响的行数</returns>
public static int ExecuteNonQuery(string sql, params SQLiteParameter[] parameters)
{
return ExecuteNonQuery(sql, CommandType.Text, parameters);
}
/// <summary>
/// 执行增、删、改
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="type">如何解释命令字符串</param>
/// <param name="parameters">可选参数</param>
/// <returns></returns>
public static int ExecuteNonQuery(string sql, CommandType type, params SQLiteParameter[] parameters)
{
using (SQLiteConnection conn = new SQLiteConnection(sConn))
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand(sql, conn);
cmd.CommandType = type;
cmd.Parameters.AddRange(parameters);
int num = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return num;
}
}

/// <summary>
/// 断开式查询，查询多个列
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="parameters">可选参数</param>
/// <returns>返回DataTable类型</returns>
public static DataTable ExecuteTable(string sql, params SQLiteParameter[] parameters)
{
return ExecuteTable(sql, CommandType.Text, parameters);
}

/// <summary>
/// 断开式查询，查询结果可为多个列
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="type">如何解释命令字符串</param>
/// <param name="parameters">可选参数</param>
/// <returns></returns>
public static DataTable ExecuteTable(string sql, CommandType type, params SQLiteParameter[] parameters)
{
SQLiteConnection conn = new SQLiteConnection(sConn);
conn.Open();
SQLiteCommand cmd = new SQLiteCommand(sql, conn);
cmd.CommandType = type;
cmd.Parameters.AddRange(parameters);
SQLiteDataAdapter sda = new SQLiteDataAdapter(cmd);
DataSet ds = new DataSet();
sda.Fill(ds);
conn.Close();
DataTable dt = ds.Tables[0];
return dt;
}
}