简介

使用SQLite进行讲解

1.基础类：

SQLiteConnection	连接数据库
SQLiteCommand	执行命令（增，删，改，查），或存储过程
SQLiteDataReader	读取查询到的数据

2.SQLiteCommand讲解

 

CommandType	获取或设置Command对象要执行命令的类型
CommandText	获取或设置要对数据库执行的SQL语句或存储过程名或表名
CommandTimeOut	获取或设置在终止对执行命令的尝试并生成错误之前的等待时间
Parameters	获取Command对象需要使用的参数集合
ExecuteScalar	执行命令（查）返回数据中第一行第一列的值。
ExecuteNonQuery	执行命令（增，删，改，查）
ExecuteReader	执行命令（查）返回查到的所有数据

 

一.下载SQLite库

二.使用

1.连接

$@"Data Source={Application.StartupPath}\Test.db;Password=;Version=3;"

2.增

private void btnAdd_Click(object sender, EventArgs e)        {            string name = "张三";            int age = 19;            using (SQLiteConnection conn = new SQLiteConnection(connStrl))            {                conn.Open();                using (SQLiteCommand cmd = conn.CreateCommand())                {                    cmd.CommandText = "insert into test(name,age) values(@name,@age);";                    cmd.Parameters.AddWithValue("@name", name);                    cmd.Parameters.AddWithValue("@age", age);                    cmd.ExecuteNonQuery();                }                conn.Close();            }        }

 

3.删

private void btnDelete_Click(object sender, EventArgs e)        {            string name = "张三";            try            {                using (SQLiteConnection conn = new SQLiteConnection(connStrl))                {                    conn.Open();                    using (SQLiteCommand cmd = conn.CreateCommand())                    {                        cmd.CommandText = $"delete from test where name=@name";                        cmd.Parameters.AddWithValue("@name", name);                        cmd.ExecuteNonQuery();                    }                    conn.Close();                }            }            catch (Exception)            {                throw;            }        }

 

4.改

private void btnUpdate_Click(object sender, EventArgs e)        {            string nameOld = "张一";            string nameNew = "张四";            try            {                using (SQLiteConnection conn = new SQLiteConnection(connStrl))                {                    conn.Open();                    using (SQLiteCommand cmd = conn.CreateCommand())                    {                        cmd.CommandText = $"update test set name=@nameNew where name=@nameOld";                        cmd.Parameters.AddWithValue("@nameOld", nameOld);                        cmd.Parameters.AddWithValue("@nameNew", nameNew);                        cmd.ExecuteNonQuery();                    }                    conn.Close();                }            }            catch (Exception)            {                throw;            }        }

 

5.查

private void btnSelect_Click(object sender, EventArgs e)        {            textBox1.Text = "";            try            {                using (SQLiteConnection conn = new SQLiteConnection(connStrl))                {                    conn.Open();                    using (SQLiteCommand cmd = conn.CreateCommand())                    {                        cmd.CommandText = "select name,age from test";                        using (SQLiteDataReader reader = cmd.ExecuteReader())                        {                            if (reader.HasRows)                                while (reader.Read())                                {                                    string name = reader.GetString(0);                                    int age = reader.GetInt32(1);                                    textBox1.Text += $"name:{name} age:{age}\r\n";                                }                        }                    }                }            }            catch (Exception)            {                throw;            }        }