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C#如何操作SQLite实现数据的增删改查

发表于:2025-02-07 作者:千家信息网编辑
千家信息网最后更新 2025年02月07日,这篇文章主要介绍了C#如何操作SQLite实现数据的增删改查,具有一定借鉴价值,感兴趣的朋友可以参考下,希望大家阅读完这篇文章之后大有收获,下面让小编带着大家一起了解一下。简介SQLite是一个轻量级
千家信息网最后更新 2025年02月07日C#如何操作SQLite实现数据的增删改查

这篇文章主要介绍了C#如何操作SQLite实现数据的增删改查,具有一定借鉴价值,感兴趣的朋友可以参考下,希望大家阅读完这篇文章之后大有收获,下面让小编带着大家一起了解一下。

简介

SQLite是一个轻量级、跨平台的关系型数据库,在小型项目中,方便,易用,同时支持多种开发语言,下面是我用C#语言对SQLite 的一个封装。

Winfrom界面如下:

代码还需要改进部分:

下面的代码我不觉得是完美的,读者可以自己去实现这些功能:

1.如果不想用多线程可以去掉UsingLock.cs ,在SQLiteHelper.cs中删除对应的引用即可。

2.创建数据库文件,可以从代码中分离成单独的方法。比如创建有密码的数据库文件。

3.在执行SQL语句时,有些语句执行成功,也不会有影响行数。比如,创建表,删除表,此时执行SQL语句返回的影响行数就为0。

4.只要SQL语句不报错就是执行成功的,在方法的返回值可以改为多个,比如用

Tuple 第一个参数 bool 代表执行结果,第二个参数 string 代表错误信息,第三个参数 int 代表影响的行数。

同样,也可以这样:

Tuple 第一个参数 bool 代表执行结果,第二个参数 string 代表错误信息,第三个参数 DataSet 代表返回的表单数据。

主要代码

SQLiteHelper.cs

using System;using System.Collections.Generic;using System.Data;using System.Data.Common;using System.Data.SQLite;using System.IO;using System.Text; namespace MySQLiteHelper{    public class SQLiteHelper    {        #region 字段                ///         /// 事务的基类        ///         private DbTransaction DBtrans;        ///         /// 使用静态变量字典解决多线程实例本类,实现一个数据库对应一个clslock        ///         private static readonly Dictionary RWL = new Dictionary();        ///         /// 数据库地址        ///         private readonly string mdataFile;        ///         /// 数据库密码        ///         private readonly string mPassWord;        private readonly string LockName = null;        ///         /// 数据库连接定义        ///         private SQLiteConnection mConn;         #endregion         #region 构造函数         ///         /// 根据数据库地址初始化        ///         /// 数据库地址        public SQLiteHelper(string dataFile)        {            this.mdataFile = dataFile ?? throw new ArgumentNullException("dataFile=null");            //this.mdataFile = AppDomain.CurrentDomain.BaseDirectory + dataFile;            this.mdataFile = dataFile;            if (!RWL.ContainsKey(dataFile))            {                LockName = dataFile;                RWL.Add(dataFile, new ClsLock());            }        }         ///         /// 使用密码打开数据库        ///         /// 数据库地址        /// 数据库密码        public SQLiteHelper(string dataFile, string PassWord)        {            this.mdataFile = dataFile ?? throw new ArgumentNullException("dataFile is null");            this.mPassWord = PassWord ?? throw new ArgumentNullException("PassWord is null");            //this.mdataFile = AppDomain.CurrentDomain.BaseDirectory + dataFile;            this.mdataFile = dataFile;            if (!RWL.ContainsKey(dataFile))            {                LockName = dataFile;                RWL.Add(dataFile, new ClsLock());            }        }         #endregion         #region 打开/关闭 数据库         ///           /// 打开 SQLiteManager 使用的数据库连接          ///           public void Open()        {            if (string.IsNullOrWhiteSpace(mPassWord))            {                mConn = OpenConnection(this.mdataFile);            }            else            {                mConn = OpenConnection(this.mdataFile, mPassWord);            }            Console.WriteLine("打开数据库成功");        }         ///         /// 关闭连接        ///         public void Close()        {            if (this.mConn != null)            {                try                {                    this.mConn.Close();                    if (RWL.ContainsKey(LockName))                    {                        RWL.Remove(LockName);                    }                }                catch                {                    Console.WriteLine("关闭失败");                }            }            Console.WriteLine("关闭数据库成功");        }         #endregion         #region 事务         ///         /// 开始事务        ///         public void BeginTrain()        {            EnsureConnection();            DBtrans = mConn.BeginTransaction();        }         ///         /// 提交事务        ///         public void DBCommit()        {            try            {                DBtrans.Commit();            }            catch (Exception)            {                DBtrans.Rollback();            }        }         #endregion         #region 工具         ///           /// 打开一个SQLite数据库文件,如果文件不存在,则创建(无密码)        ///           ///           /// SQLiteConnection 类          private SQLiteConnection OpenConnection(string dataFile)        {            if (dataFile == null)            {                throw new ArgumentNullException("dataFiledataFile=null");            }            if (!File.Exists(dataFile))            {                SQLiteConnection.CreateFile(dataFile);            }            SQLiteConnection conn = new SQLiteConnection();            SQLiteConnectionStringBuilder conStr = new SQLiteConnectionStringBuilder            {                DataSource = dataFile            };            conn.ConnectionString = conStr.ToString();            conn.Open();            return conn;        }         ///           /// 打开一个SQLite数据库文件,如果文件不存在,则创建(有密码)        ///           ///           ///         /// SQLiteConnection 类          private SQLiteConnection OpenConnection(string dataFile, string Password)        {            if (dataFile == null)            {                throw new ArgumentNullException("dataFile=null");            }            if (!File.Exists(Convert.ToString(dataFile)))            {                SQLiteConnection.CreateFile(dataFile);            }            try            {                SQLiteConnection conn = new SQLiteConnection();                SQLiteConnectionStringBuilder conStr = new SQLiteConnectionStringBuilder                {                    DataSource = dataFile,                    Password = Password                };                conn.ConnectionString = conStr.ToString();                conn.Open();                return conn;            }            catch (Exception)            {                return null;            }        }         ///           /// 读取 或 设置 SQLiteManager 使用的数据库连接          ///           public SQLiteConnection Connection        {            get            {                return mConn;            }            private set            {                mConn = value ?? throw new ArgumentNullException();            }        }         ///         /// 确保数据库是连接状态        ///         ///         protected void EnsureConnection()        {            if (this.mConn == null)            {                throw new Exception("SQLiteManager.Connection=null");            }            if (mConn.State != ConnectionState.Open)            {                mConn.Open();            }        }         ///         /// 获取数据库文件的路径        ///         ///         public string GetDataFile()        {            return this.mdataFile;        }         ///           /// 判断表 table 是否存在          ///           ///           /// 存在返回true,否则返回false          public bool TableExists(string table)        {            if (table == null)            {                throw new ArgumentNullException("table=null");            }            EnsureConnection();            SQLiteDataReader reader = ExecuteReader("SELECT count(*) as c FROM sqlite_master WHERE type='table' AND name=@tableName ", new SQLiteParameter[] { new SQLiteParameter("tableName", table) });            if (reader == null)            {                return false;            }            reader.Read();            int c = reader.GetInt32(0);            reader.Close();            reader.Dispose();            //return false;              return c == 1;        }         ///         /// VACUUM 命令(通过复制主数据库中的内容到一个临时数据库文件,然后清空主数据库,并从副本中重新载入原始的数据库文件)        ///         ///         public bool Vacuum()        {            try            {                using (SQLiteCommand Command = new SQLiteCommand("VACUUM", Connection))                {                    Command.ExecuteNonQuery();                }                return true;            }            catch (System.Data.SQLite.SQLiteException)            {                return false;            }        }          #endregion         #region 执行SQL         ///         /// 执行SQL, 并返回 SQLiteDataReader 对象结果         ///           ///         /// null 表示无参数        ///           public SQLiteDataReader ExecuteReader(string sql, SQLiteParameter[] paramArr)        {            if (sql == null)            {                throw new ArgumentNullException("sql=null");            }            EnsureConnection();            using (RWL[LockName].Read())            {                using (SQLiteCommand cmd = new SQLiteCommand(sql, Connection))                {                    if (paramArr != null)                    {                        cmd.Parameters.AddRange(paramArr);                    }                    try                    {                        SQLiteDataReader reader = cmd.ExecuteReader();                        cmd.Parameters.Clear();                        return reader;                    }                    catch (Exception)                    {                        return null;                    }                }            }        }         ///         /// 执行查询,并返回dataset对象        ///         /// SQL查询语句        /// 参数数组        ///         public DataSet ExecuteDataSet(string sql, SQLiteParameter[] paramArr)        {            if (sql == null)            {                throw new ArgumentNullException("sql=null");            }            this.EnsureConnection();            using (RWL[LockName].Read())            {                using (SQLiteCommand cmd = new SQLiteCommand(sql, this.Connection))                {                    if (paramArr != null)                    {                        cmd.Parameters.AddRange(paramArr);                    }                    try                    {                        SQLiteDataAdapter da = new SQLiteDataAdapter();                        DataSet ds = new DataSet();                        da.SelectCommand = cmd;                        da.Fill(ds);                        cmd.Parameters.Clear();                        da.Dispose();                        return ds;                    }                    catch (Exception)                    {                        return null;                    }                }            }        }         ///         /// 执行SQL查询,并返回dataset对象。        ///         /// 映射源表的名称        /// SQL语句        /// SQL参数数组        ///         public DataSet ExecuteDataSet(string strTable, string sql, SQLiteParameter[] paramArr)        {            if (sql == null)            {                throw new ArgumentNullException("sql=null");            }            this.EnsureConnection();            using (RWL[LockName].Read())            {                using (SQLiteCommand cmd = new SQLiteCommand(sql, this.Connection))                {                    if (paramArr != null)                    {                        cmd.Parameters.AddRange(paramArr);                    }                    try                    {                        SQLiteDataAdapter da = new SQLiteDataAdapter();                        DataSet ds = new DataSet();                        da.SelectCommand = cmd;                        da.Fill(ds, strTable);                        cmd.Parameters.Clear();                        da.Dispose();                        return ds;                    }                    catch (Exception)                    {                        return null;                    }                }            }        }         ///           /// 执行SQL,返回受影响的行数,可用于执行表创建语句,paramArr == null 表示无参数        ///           ///           ///           public int ExecuteNonQuery(string sql, SQLiteParameter[] paramArr)        {            if (sql == null)            {                throw new ArgumentNullException("sql=null");            }            this.EnsureConnection();            using (RWL[LockName].Read())            {                try                {                    using (SQLiteCommand cmd = new SQLiteCommand(sql, Connection))                    {                        if (paramArr != null)                        {                            foreach (SQLiteParameter p in paramArr)                            {                                cmd.Parameters.Add(p);                            }                        }                        int c = cmd.ExecuteNonQuery();                        cmd.Parameters.Clear();                        return c;                    }                }                catch (SQLiteException)                {                    return 0;                }            }        }         ///           /// 执行SQL,返回结果集第一行,如果结果集为空,那么返回空 List(List.Count=0),         /// rowWrapper = null 时,使用 WrapRowToDictionary          ///           ///           ///           ///           public object ExecuteScalar(string sql, SQLiteParameter[] paramArr)        {            if (sql == null)            {                throw new ArgumentNullException("sql=null");            }            this.EnsureConnection();            using (RWL[LockName].Read())            {                using (SQLiteCommand cmd = new SQLiteCommand(sql, Connection))                {                    if (paramArr != null)                    {                        cmd.Parameters.AddRange(paramArr);                    }                    try                    {                        object reader = cmd.ExecuteScalar();                        cmd.Parameters.Clear();                        cmd.Dispose();                        return reader;                    }                    catch (Exception)                    {                        return null;                    }                }            }        }         ///           /// 查询一行记录,无结果时返回 null,conditionCol = null 时将忽略条件,直接执行 select * from table           ///           /// 表名          ///           ///           ///           public object QueryOne(string table, string conditionCol, object conditionVal)        {            if (table == null)            {                throw new ArgumentNullException("table=null");            }            this.EnsureConnection();            string sql = "select * from " + table;            if (conditionCol != null)            {                sql += " where " + conditionCol + "=@" + conditionCol;            }            object result = ExecuteScalar(sql, new SQLiteParameter[] { new SQLiteParameter(conditionCol, conditionVal) });            return result;        }         #endregion         #region 增 删 改         ///           /// 执行 insert into 语句         ///           ///           ///           ///           public int InsertData(string table, Dictionary entity)        {            if (table == null)            {                throw new ArgumentNullException("table=null");            }            this.EnsureConnection();            string sql = BuildInsert(table, entity);            return this.ExecuteNonQuery(sql, BuildParamArray(entity));        }         ///           /// 执行 update 语句,注意:如果 where = null,那么 whereParams 也为 null,        ///           /// 表名          /// 要修改的列名和列名的值          /// 查找符合条件的列          /// where条件中参数的值          ///           public int Update(string table, Dictionary entity, string where, SQLiteParameter[] whereParams)        {            if (table == null)            {                throw new ArgumentNullException("table=null");            }            this.EnsureConnection();            string sql = BuildUpdate(table, entity);            SQLiteParameter[] parameter = BuildParamArray(entity);            if (where != null)            {                sql += " where " + where;                if (whereParams != null)                {                    SQLiteParameter[] newArr = new SQLiteParameter[(parameter.Length + whereParams.Length)];                    Array.Copy(parameter, newArr, parameter.Length);                    Array.Copy(whereParams, 0, newArr, parameter.Length, whereParams.Length);                    parameter = newArr;                }            }            return this.ExecuteNonQuery(sql, parameter);        }         ///           /// 执行 delete from table 语句,where不必包含'where'关键字,where = null 时将忽略 whereParams          ///           ///           ///           ///           ///           public int Delete(string table, string where, SQLiteParameter[] whereParams)        {            if (table == null)            {                throw new ArgumentNullException("table=null");            }            this.EnsureConnection();            string sql = "delete from " + table + " ";            if (where != null)            {                sql += "where " + where;            }            return ExecuteNonQuery(sql, whereParams);        }         ///         /// 将 Dictionary 类型数据 转换为 SQLiteParameter[] 类型        ///         ///         ///         private SQLiteParameter[] BuildParamArray(Dictionary entity)        {            List list = new List();            foreach (string key in entity.Keys)            {                list.Add(new SQLiteParameter(key, entity[key]));            }            if (list.Count == 0)            {                return null;            }            return list.ToArray();        }         ///         /// 将 Dictionary 类型数据 转换为 插入数据 的 SQL语句        ///         /// 表名        /// 字典        ///         private string BuildInsert(string table, Dictionary entity)        {            StringBuilder buf = new StringBuilder();            buf.Append("insert into ").Append(table);            buf.Append(" (");            foreach (string key in entity.Keys)            {                buf.Append(key).Append(",");            }            buf.Remove(buf.Length - 1, 1); // 移除最后一个,            buf.Append(") ");            buf.Append("values(");            foreach (string key in entity.Keys)            {                buf.Append("@").Append(key).Append(","); // 创建一个参数            }            buf.Remove(buf.Length - 1, 1);            buf.Append(") ");             return buf.ToString();        }         ///         /// 将 Dictionary 类型数据 转换为 修改数据 的 SQL语句        ///         /// 表名        /// 字典        ///         private string BuildUpdate(string table, Dictionary entity)        {            StringBuilder buf = new StringBuilder();            buf.Append("update ").Append(table).Append(" set ");            foreach (string key in entity.Keys)            {                buf.Append(key).Append("=").Append("@").Append(key).Append(",");            }            buf.Remove(buf.Length - 1, 1);            buf.Append(" ");            return buf.ToString();        }         #endregion    }}

UsingLock.cs

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Threading; namespace MySQLiteHelper{    ///     /// 使用using代替lock操作的对象,可指定写入和读取锁定模式    ///     public sealed class ClsLock    {        #region 内部类         ///         /// 利用IDisposable的using语法糖方便的释放锁定操作内部类        ///         private struct Lock : IDisposable        {            ///             /// 读写锁对象            ///             private readonly ReaderWriterLockSlim _Lock;            ///             /// 是否为写入模式            ///             private bool _IsWrite;            ///             /// 利用IDisposable的using语法糖方便的释放锁定操作构造函数            ///             /// 读写锁            /// 写入模式为true,读取模式为false            public Lock(ReaderWriterLockSlim rwl, bool isWrite)            {                _Lock = rwl;                _IsWrite = isWrite;            }            ///             /// 释放对象时退出指定锁定模式            ///             public void Dispose()            {                if (_IsWrite)                {                    if (_Lock.IsWriteLockHeld)                    {                        _Lock.ExitWriteLock();                    }                }                else                {                    if (_Lock.IsReadLockHeld)                    {                        _Lock.ExitReadLock();                    }                }            }        }         ///         /// 空的可释放对象,免去了调用时需要判断是否为null的问题内部类        ///         private class Disposable : IDisposable        {            ///             /// 空的可释放对象            ///             public static readonly Disposable Empty = new Disposable();            ///             /// 空的释放方法            ///             public void Dispose() { }        }         #endregion         ///         /// 读写锁        ///         private readonly ReaderWriterLockSlim _LockSlim = new ReaderWriterLockSlim();        ///         /// 使用using代替lock操作的对象,可指定写入和读取锁定模式构造函数        ///         public ClsLock()        {            Enabled = true;        }        ///         /// 是否启用,当该值为false时,Read()和Write()方法将返回 Disposable.Empty        ///         public bool Enabled { get; set; }         ///          /// 进入读取锁定模式,该模式下允许多个读操作同时进行,        /// 退出读锁请将返回对象释放,建议使用using语块,        /// Enabled为false时,返回Disposable.Empty,        /// 在读取或写入锁定模式下重复执行,返回Disposable.Empty;        ///         public IDisposable Read()        {            if (Enabled == false || _LockSlim.IsReadLockHeld || _LockSlim.IsWriteLockHeld)            {                return Disposable.Empty;            }            else            {                _LockSlim.EnterReadLock();                return new Lock(_LockSlim, false);            }        }         ///          /// 进入写入锁定模式,该模式下只允许同时执行一个读操作,        /// 退出读锁请将返回对象释放,建议使用using语块,        /// Enabled为false时,返回Disposable.Empty,        /// 在写入锁定模式下重复执行,返回Disposable.Empty        ///         /// 读取模式下不能进入写入锁定状态        public IDisposable Write()        {            if (Enabled == false || _LockSlim.IsWriteLockHeld)            {                return Disposable.Empty;            }            else if (_LockSlim.IsReadLockHeld)            {                throw new NotImplementedException("读取模式下不能进入写入锁定状态");            }            else            {                _LockSlim.EnterWriteLock();                return new Lock(_LockSlim, true);            }        }    } }

Form1.cs

using MySQLiteHelper;using System;using System.Collections.Generic;using System.Data;using System.Data.SQLite;using System.Windows.Forms; namespace SQLiteDemo{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }         private SQLiteHelper SQLiteHelpers = null;        private const string DBAddress = "D:\\SQLiteData\\test_record.db3";         private void Form1_Load(object sender, EventArgs e)        {            SQLiteHelpers = new SQLiteHelper(DBAddress,"123456");        }         ///         /// 打开数据库        ///         ///         ///         private void Button_OpenDB_Click(object sender, EventArgs e)        {            SQLiteHelpers.Open();            Label_DBOpenState.Text = "打开";        }         ///         /// 关闭数据库        ///         ///         ///         private void Button_CloseDB_Click(object sender, EventArgs e)        {            SQLiteHelpers.Close();            Label_DBOpenState.Text = "关闭";        }         ///         /// 查询        ///         ///         ///         private void Button_Query_Click(object sender, EventArgs e)        {            SQLiteParameter[] parameter = new SQLiteParameter[]            {                new SQLiteParameter("address", "济南")            };            string sql = "SELECT * FROM student WHERE address = @address";            DataSet dataSet = SQLiteHelpers.ExecuteDataSet(sql, parameter);            if (dataSet != null)            {                dataGridView1.DataSource = dataSet.Tables[0];            }        }         ///         /// 插入数据        ///         ///         ///         private void Button_Add_Click(object sender, EventArgs e)        {            Dictionary dic = new Dictionary();            dic.Add("ID", 6);            dic.Add("name", "王二麻子");            dic.Add("age", 44);            dic.Add("address", "陕西");             int result = SQLiteHelpers.InsertData("student", dic);            Console.WriteLine("插入结果,受影响的行数:" + result);        }         ///         /// 修改数据        ///         ///         ///         private void Button_Modify_Click(object sender, EventArgs e)        {            Dictionary dic = new Dictionary();            //将列名 name 的值改为 "猴子"            dic.Add("name", "猴子");            //将列名 address 的值改为 花果山            dic.Add("address", "花果山");            //where条件            string where = "ID = @ID AND age = @Age";            //where条件中对应的参数            SQLiteParameter[] parameter = new SQLiteParameter[]            {                new SQLiteParameter("ID", 4),                new SQLiteParameter("Age",23)            };                        int result = SQLiteHelpers.Update("student", dic, where, parameter);            Console.WriteLine("修改结果,受影响的行数:" + result);        }         ///         /// 删除数据        ///         ///         ///         private void Button_Delete_Click(object sender, EventArgs e)        {            //where条件            string where = "ID = @ID";            //where条件中对应的参数            SQLiteParameter[] parameter = new SQLiteParameter[]            {                new SQLiteParameter("ID", 6),            };             int result = SQLiteHelpers.Delete("student", where, parameter);            Console.WriteLine("删除结果,受影响的行数:" + result);        }         ///         /// 判断表是否存在        ///         ///         ///         private void Button_TableExists_Click(object sender, EventArgs e)        {            string title = "dddd";            bool result = SQLiteHelpers.TableExists(title);            Console.WriteLine(string.Format("{0} 表是否存在,结果:{1}", title, result));        }         //输出各表中的数据        //public static void PrintValues(DataSet ds)        //{        //    foreach (DataTable table in ds.Tables)        //    {        //        Console.WriteLine("表名称:" + table.TableName);        //        foreach (DataRow row in table.Rows)        //        {        //            foreach (DataColumn column in table.Columns)        //            {        //                Console.Write(row[column] + "");        //            }        //            Console.WriteLine();        //        }        //    }        //}     }}

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