1. In the project project, open NuGet and search for Stub.System.Data.SQLite.Core.NetFramework.
2. Start the installation after searching. After the installation is complete, System.data.sqlite appears in the project reference, and it can be used at this time.
3. Use the following code as a database helper class, and quickly use the Sqlite database. (This method has been tested in both wpf and winform)
public class DataBaseHelp
{
/// <summary>
/// 链接套接字
/// </summary>
static SQLiteConnection m_dbConnection {
get; set; }
/// <summary>
/// 生成连接字符串
/// </summary>
/// <returns></returns>
private static string CreateConnectionString(string db)
{
SQLiteConnectionStringBuilder connectionString = new SQLiteConnectionStringBuilder();
connectionString.DataSource = @"data/" + db;//此处文件名可以使用变量表示
string conStr = connectionString.ToString();
return conStr;
}
/// <summary>
/// 连接到数据库
/// </summary>
/// <returns></returns>
private static SQLiteConnection dbConnection(string db)
{
m_dbConnection = new SQLiteConnection(CreateConnectionString(db));
m_dbConnection.Open();
return m_dbConnection;
}
/// <summary>
/// 创建数据库文件,如：text.db
/// </summary>
/// <param name="fileName">文件名</param>
public static void CreateDBFile(string fileName)
{
string path = Environment.CurrentDirectory + @"/Data/";
if (!Directory.Exists(path))
{
Directory.CreateDirectory(path);
}
string databaseFileName = path + fileName;
if (!File.Exists(databaseFileName))
{
SQLiteConnection.CreateFile(databaseFileName);
}
}
/// <summary>
/// 在指定数据库中创建一个table
/// 如：create table mytab (ID INT PRIMARY KEY NOT NULL, text TEXT NOT NULL);
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
public static bool CreateTable(string db, string sql)
{
try
{
SQLiteCommand command = new SQLiteCommand(sql, dbConnection(db));
command.ExecuteNonQuery();
return true;
}
catch (Exception ex)
{
Console.WriteLine("ExecuteNonQuery(" + sql + ")Err:" + ex);
return false;
}
finally
{
closeConn();
}
}
/// <summary>
/// 返回记录集查询
/// </summary>
/// <param name="sql">sql查询语言</param>
/// <returns>返回查询结果集</returns>
public static DataTable SqlTable(string db, string sql)
{
try
{
SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection(db));//sql语句
sqlcmd.CommandTimeout = 120;
SQLiteDataReader reader = sqlcmd.ExecuteReader();
DataTable dt = new DataTable();
if (reader != null)
{
dt.Load(reader, LoadOption.PreserveChanges, null);
}
return dt;
}
catch (Exception ex)
{
Console.WriteLine("SqlReader(" + sql + ")Err:" + ex);
return null;
}
finally
{
closeConn();
}
}
/// <summary>
/// 执行增删改查操作
/// </summary>
/// <param name="sql">查询语言</param>
/// <returns></returns>
public static int ExecuteNonQuery(string db, string sql)
{
try
{
SQLiteCommand cmd;
cmd = new SQLiteCommand(sql, dbConnection(db));
cmd.ExecuteNonQuery().ToString();
return 1;
}
catch (Exception ex)
{
string chejnji="ExecuteNonQuery(" + sql + ")Err:" + ex.Message;
var strDateInfo = "出现应用程序未处理的异常：" + DateTime.Now + "\r\n";
var str = string.Format(strDateInfo + "异常类型：{0}\r\n异常消息：{1}\r\n异常信息：{2}\r\n",
ex.GetType().Name, ex.Message, ex.StackTrace);
WriteLog(str+ chejnji);//日志写入
return 0;
}
finally
{
closeConn();
}
}
static void WriteLog(string str)
{
if (!Directory.Exists("ErrLog"))
{
Directory.CreateDirectory("ErrLog");
}
string CreateTime = DateTime.Now.ToString("yyyy-MM");
using (var sw = new StreamWriter("ErrLog\\" + CreateTime + ".txt", true))
{
sw.WriteLine(str);
sw.WriteLine("---------------------------------------------------------");
sw.Close();
}
}
/// <summary>
/// 删除数据库
/// </summary>
/// <param name="fileName">文件名</param>
public static void DeleteDBFile(string fileName)
{
string path = Environment.CurrentDirectory + @"/Data/" + fileName;
if (File.Exists(path))
{
File.Delete(path);
}
}
/// <summary>
/// 在指定数据库中删除一个table
/// </summary>
/// <param name="tablename">表名称</param>
/// <returns></returns>
public static bool DeleteTable(string db, string tablename)
{
try
{
SQLiteCommand cmd = new SQLiteCommand("DROP TABLE IF EXISTS " + tablename, dbConnection(db));
cmd.ExecuteNonQuery();
return true;
}
catch (Exception ex)
{
Console.WriteLine("ExecuteNonQuery(DROP TABLE IF EXISTS " + tablename + ")Err:" + ex);
return false;
}
finally
{
closeConn();
}
}
/// <summary>
/// 返回一条记录查询
/// </summary>
/// <param name="sql">sql查询语言</param>
/// <returns>返回字符串数组</returns>
public static List<string> SqlRow(string db, string sql)
{
try
{
SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection(db));//sql语句
SQLiteDataReader reader = sqlcmd.ExecuteReader();
if (!reader.Read())
{
return null;
}
List<string> Row = new List<string>();
for (int i = 0; i < reader.FieldCount; i++)
{
Row.Add(reader[i].ToString());
}
reader.Close();
return Row;
}
catch (Exception ex)
{
Console.WriteLine("SqlRow(" + sql + ")Err:" + ex);
return null;
}
finally
{
closeConn();
}
}
/// <summary>
/// 在指定表中添加列
/// </summary>
/// <param name="tablename">表名</param>
/// <param name="columnname">列名</param>
/// <param name="ctype">列的数值类型</param>
/// <returns></returns>
public static bool AddColumn(string db, string tablename, string columnname, string ctype)
{
try
{
SQLiteCommand cmd = new SQLiteCommand("ALTER TABLE " + tablename + " ADD COLUMN " + columnname + " " + ctype, dbConnection(db));
cmd.ExecuteNonQuery();
return true;
}
catch (Exception ex)
{
Console.WriteLine("ExecuteNonQuery(ALTER TABLE " + tablename + " ADD COLUMN " + columnname + " " + ctype + ")Err:" + ex);
return false;
}
finally
{
closeConn();
}
}
/// <summary>
/// 唯一结果查询
/// </summary>
/// <param name="sql">sql查询语言</param>
/// <returns>返回一个字符串</returns>
public static string sqlone(string db, string sql)
{
try
{
SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection(db));//sql语句
return sqlcmd.ExecuteScalar().ToString();
}
catch
{
return "";
}
finally
{
closeConn();
}
}
/// <summary>
/// 获取一列数据
/// </summary>
/// <param name="sql">单列查询</param>
/// <param name="count">返回结果数量</param>
/// <returns>返回一个数组</returns>
public static List<string> sqlcolumn(string db, string sql)
{
try
{
List<string> Column = new List<string>();
SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection(db));//sql语句
SQLiteDataReader reader = sqlcmd.ExecuteReader();
while (reader.Read())
{
Column.Add(reader[0].ToString());
}
reader.Close();
return Column;
}
catch (Exception ex)
{
Console.WriteLine("sqlcolumn(" + sql + ")Err:" + ex);
return null;
}
finally
{
closeConn();
}
}
/// <summary>
/// 关闭数据库连接
/// </summary>
public static void closeConn()
{
try
{
if (m_dbConnection.State == ConnectionState.Open)
m_dbConnection.Close();
else if (m_dbConnection.State == ConnectionState.Broken)
{
m_dbConnection.Close();
}
}
catch (Exception ex)
{
Console.WriteLine("closeConnErr:" + ex);
}
}
}