1、在nuget 工具中安装 “System.Data.SQLite”插件;
2、将数据库文件放在DEBUG目录下(表文件可以通过navicate 建立也);
3、创建DbHelperSQLite.cs文件,指定数据库路径等信息;
using System; using System.Collections; using System.Data.Common; using System.Data; using System.Data.SQLite; using System.IO; using System.Windows.Forms; namespace WordWrite { public class DBHelperSQLite { public static string dataBaseFileName = AppDomain.CurrentDomain.BaseDirectory + "goods.db"; public static string connectionString = @"Data Source=" + dataBaseFileName + "; Pooling=true;FailIfMissing=false;"; public DBHelperSQLite() { } public static void ExistsDataBase() { if (!File.Exists(dataBaseFileName)) { SQLiteConnection.CreateFile(dataBaseFileName); } if (!ExixtsTable("PointManage")) { ExecuteSql(@"CREATE TABLE PointManage( Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, PointAddress TEXT NOT NULL, PointDes TEXT NOT NULL )"); } if (!ExixtsTable("PointValue")) { ExecuteSql(@"CREATE TABLE PointValue( Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, PointAddress TEXT NOT NULL, Time TEXT NOT NULL, Value NUMERIC NOT NULL )"); ExecuteSql("CREATE INDEX PointAddress ON PointValue(PointAddress COLLATE BINARY ASC)"); ExecuteSql("CREATE INDEX Time ON PointValue(Time COLLATE BINARY ASC)"); } } #region 公用方法 public static bool ExixtsTable(string tableName) { string sqlStr = $"SELECT count(*) from sqlite_master where type='table' and name='{tableName}'"; using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { using (SQLiteCommand cmd = new SQLiteCommand(sqlStr, connection)) { try { connection.Open(); return !(Convert.ToInt32(cmd.ExecuteScalar()) == 0);//不存在此表,返回false } catch (SQLiteException E) { connection.Close(); throw new Exception(E.Message); } } } } 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 (Equals(obj, null) || Equals(obj, 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 (Equals(obj, null) || Equals(obj, 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> /// 对SQLite数据库执行增删改操作,返回受影响的行数。 /// </summary> /// <param name="sql">要执行的增删改的SQL语句</param> /// <param name="parameters">执行增删改语句所需要的参数,参数必须以它们在SQL语句中的顺序为准</param> /// <returns></returns> public static int ExecuteNonQuery(string sql, SQLiteParameter[] parameters) { int affectedRows = 0; using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { connection.Open(); using (DbTransaction transaction = connection.BeginTransaction()) { using (SQLiteCommand command = new SQLiteCommand(connection)) { command.CommandText = sql; if (parameters != null) { command.Parameters.AddRange(parameters); } affectedRows = command.ExecuteNonQuery(); } transaction.Commit(); } } return affectedRows; } /// <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 (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 (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 (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 (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 (Equals(obj, null) || Equals(obj, DBNull.Value)) { return null; } else { return obj; } } catch (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 (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 (SQLiteException ex) { MessageBox.Show(ex.Message); return null; //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 (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 (Equals(obj, null) || Equals(obj, DBNull.Value)) { return null; } else { return obj; } } catch (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 (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 (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); } } /// <summary> /// 同步datagridview表中的数据至数据库,要求单表,有主键; /// </summary> /// <param name="ds "></param> /// <param name="strTblName"> 要更新的表名 </param> /// <returns></returns> public static int UpdateDataTable(DataTable dt, string strTblName) { int num2 = -1; using (SQLiteConnection connection = new SQLiteConnection(connectionString)) { using (SQLiteCommand cmd = new SQLiteCommand()) { cmd.CommandText = "SELECT * FROM " + strTblName + " where 1=2 "; try { SQLiteDataAdapter myAdapter = new SQLiteDataAdapter(cmd); myAdapter.SelectCommand.Connection = connection; //自动生成单表命令,用于将对DataSet所做的更改与数据库更改相对应 SQLiteCommandBuilder myCommandBuilder = new SQLiteCommandBuilder(myAdapter); myAdapter.Update(dt); } catch (SQLiteException e) { throw new Exception(e.Message); } finally { } } } return 0; } #endregion } }
标签:SQLite,c#,数据库,cmd,connection,SQLiteConnection,using,new,SQLiteCommand From: https://www.cnblogs.com/lrzy/p/18096299