C#访问SQLite数据库，实现数据的增删改查功能
说明：本文的代码是基于Winform中举例的，经过实测可用。
1.封装Sqlite操作类：sqLiteHelper
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SQLite;
namespace TestSqlite.sq
{
///
/// SQLite 操作类
///
public class SqLiteHelper
{
///
/// 数据库连接定义
///
public SQLiteConnection dbConnection;
///
/// SQL命令定义
///
private SQLiteCommand dbCommand;
///
/// 数据读取定义
///
private SQLiteDataReader dataReader;
///
/// 数据库连接字符串定义
///
private SQLiteConnectionStringBuilder dbConnectionstr;
///
/// 构造函数
///
/// 连接SQLite库字符串
public SqLiteHelper(string connectionString)
{
try
{
dbConnection = new SQLiteConnection();
dbConnectionstr = new SQLiteConnectionStringBuilder();
dbConnectionstr.DataSource = connectionString;
dbConnectionstr.Password = "admin"; //设置密码，SQLite ADO.NET实现了数据库密码保护
dbConnection.ConnectionString = dbConnectionstr.ToString();
dbConnection.Open();
}
catch (Exception e)
{
Log(e.ToString());
}
}
///
/// 执行SQL命令
///
/// The query.
/// SQL命令字符串
public SQLiteDataReader ExecuteQuery(string queryString)
{
try
{
dbCommand = dbConnection.CreateCommand();
dbCommand.CommandText = queryString; //设置SQL语句
dataReader = dbCommand.ExecuteReader();
}
catch (Exception e)
{
Log(e.Message);
}
return dataReader;
}
///
/// 关闭数据库连接
///
public void CloseConnection()
{
//销毁Command
if (dbCommand != null)
{
dbCommand.Cancel();
}
dbCommand = null;
//销毁Reader
if (dataReader != null)
{
dataReader.Close();
}
dataReader = null;
//销毁Connection
if (dbConnection != null)
{
dbConnection.Close();
}
dbConnection = null;
}
///
/// 读取整张数据表
///
/// The full table.
/// 数据表名称
public SQLiteDataReader ReadFullTable(string tableName)
{
string queryString = "SELECT * FROM " + tableName; //获取所有可用的字段
return ExecuteQuery(queryString);
}
///
/// 向指定数据表中插入数据
///
/// The values.
/// 数据表名称
/// 插入的数值
public SQLiteDataReader InsertValues(string tableName, string[] values)
{
//获取数据表中字段数目
int fieldCount = ReadFullTable(tableName).FieldCount;
//当插入的数据长度不等于字段数目时引发异常
if (values.Length != fieldCount)
{
throw new SQLiteException("values.Length!=fieldCount");
}
string queryString = "INSERT INTO " + tableName + " VALUES (" + "'" + values[0] + "'";
for (int i = 1; i < values.Length; i++)
{
queryString += ", " + "'" + values[i] + "'";
}
queryString += " )";
return ExecuteQuery(queryString);
}
///
/// 更新指定数据表内的数据
///
/// The values.
/// 数据表名称
/// 字段名
/// 字段名对应的数据
/// 关键字
/// 关键字对应的值
/// 运算符：=,<,>,...，默认“=”
public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues, string key, string value, string operation)
{
// operation="="; //默认
//当字段名称和字段数值不对应时引发异常
if (colNames.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length!=colValues.Length");
}
string queryString = "UPDATE " + tableName + " SET " + colNames[0] + "=" + "'" + colValues[0] + "'";
for (int i = 1; i < colValues.Length; i++)
{
queryString += ", " + colNames[i] + "=" + "'" + colValues[i] + "'";
}
queryString += " WHERE " + key + operation + "'" + value + "'";
return ExecuteQuery(queryString);
}
///
/// 更新指定数据表内的数据
///
/// The values.
/// 数据表名称
/// 字段名
/// 字段名对应的数据
/// 关键字
/// 关键字对应的值
/// 运算符：=,<,>,...，默认“=”
public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues, string key1, string value1, string operation, string key2, string value2)
{
// operation="="; //默认
//当字段名称和字段数值不对应时引发异常
if (colNames.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length!=colValues.Length");
}
string queryString = "UPDATE " + tableName + " SET " + colNames[0] + "=" + "'" + colValues[0] + "'";
for (int i = 1; i < colValues.Length; i++)
{
queryString += ", " + colNames[i] + "=" + "'" + colValues[i] + "'";
}
//表中已经设置成int类型的不需要再次添加‘单引号’，而字符串类型的数据需要进行添加‘单引号’
queryString += " WHERE " + key1 + operation + "'" + value1 + "'" + "OR " + key2 + operation + "'" + value2 + "'";
return ExecuteQuery(queryString);
}
///
/// 删除指定数据表内的数据
///
/// The values.
/// 数据表名称
/// 字段名
/// 字段名对应的数据
public SQLiteDataReader DeleteValuesOR(string tableName, string[] colNames, string[] colValues, string[] operations)
{
//当字段名称和字段数值不对应时引发异常
if (colNames.Length != colValues.Length || operations.Length != colNames.Length || operations.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length!=colValues.Length || operations.Length!=colNames.Length || operations.Length!=colValues.Length");
}
string queryString = "DELETE FROM " + tableName + " WHERE " + colNames[0] + operations[0] + "'" + colValues[0] + "'";
for (int i = 1; i < colValues.Length; i++)
{
queryString += "OR " + colNames[i] + operations[0] + "'" + colValues[i] + "'";
}
return ExecuteQuery(queryString);
}
///
/// 删除指定数据表内的数据
///
/// The values.
/// 数据表名称
/// 字段名
/// 字段名对应的数据
public SQLiteDataReader DeleteValuesAND(string tableName, string[] colNames, string[] colValues, string[] operations)
{
//当字段名称和字段数值不对应时引发异常
if (colNames.Length != colValues.Length || operations.Length != colNames.Length || operations.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length!=colValues.Length || operations.Length!=colNames.Length || operations.Length!=colValues.Length");
}
string queryString = "DELETE FROM " + tableName + " WHERE " + colNames[0] + operations[0] + "'" + colValues[0] + "'";
for (int i = 1; i < colValues.Length; i++)
{
queryString += " AND " + colNames[i] + operations[i] + "'" + colValues[i] + "'";
}
return ExecuteQuery(queryString);
}
///
/// 创建数据表
/// +
/// The table.
/// 数据表名
/// 字段名
/// 字段名类型
public SQLiteDataReader CreateTable(string tableName, string[] colNames, string[] colTypes)
{
string queryString = "CREATE TABLE IF NOT EXISTS " + tableName + "( " + colNames[0] + " " + colTypes[0];
for (int i = 1; i < colNames.Length; i++)
{
queryString += ", " + colNames[i] + " " + colTypes[i];
}
queryString += " ) ";
return ExecuteQuery(queryString);
}
///
/// Reads the table.
///
/// The table.
/// Table name.
/// Items.
/// Col names.
/// Operations.
/// Col values.
public SQLiteDataReader ReadTable(string tableName, string[] items, string[] colNames, string[] operations, string[] colValues)
{
string queryString = "SELECT " + items[0];
for (int i = 1; i < items.Length; i++)
{
queryString += ", " + items[i];
}
queryString += " FROM " + tableName + " WHERE " + colNames[0] + " " + operations[0] + " " + colValues[0];
for (int i = 0; i < colNames.Length; i++)
{
queryString += " AND " + colNames[i] + " " + operations[i] + " " + colValues[0] + " ";
}
return ExecuteQuery(queryString);
}
///
/// 本类log
///
///
static void Log(string s)
{
Console.WriteLine("class SqLiteHelper:::" + s);
}
}
}
2.Form窗体中调用sqLiteHelper类，实现数据的增删等功能
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SQLite;
using TestSqlite20180310.sq;
using System.Net;
namespace TestSqlite20180310
{
public partial class Form1 : Form
{
private SqLiteHelper sql;
private SqLiteHelper passWord;
private DataSet ds;
private SQLiteDataAdapter sda;
private bool flag = false;
public Form1()
{
InitializeComponent();
CreatePassWard();
ReadPassWardFromdb();
}
private void btnTest_Click(object sender, EventArgs e)
{
try
{
// sql = new SqLiteHelper("data source=mydb.db");
sql = new SqLiteHelper("mydb.db");
//创建名为table1的数据表
sql.CreateTable("table1", new string[] { "ID", "Name", "Age", "Email" }, new string[] { "INTEGER", "TEXT", "INTEGER", "TEXT" });
//插入两条数据
sql.InsertValues("table1", new string[] { "1", "张三", "16", "[email protected]" });
sql.InsertValues("table1", new string[] { "2", "李四", "17", "[email protected]" });
//更新数据，将Name="张三"的记录中的Name改为"小三"
sql.UpdateValues("table1", new string[] { "Name" }, new string[] { "sunlei" }, "Name", "小三", "=");
//删除Name="小三"且Age=16的记录,DeleteValuesOR方法类似
sql.DeleteValuesAND("table1", new string[] { "Name", "Age" }, new string[] { "小三", "16" }, new string[] { "=", "=" });
//读取整张表
SQLiteDataReader reader = sql.ReadFullTable("table1");
while (reader.Read())
{
//读取ID
Log("" + reader.GetInt32(reader.GetOrdinal("ID")));
//读取Name
Log("" + reader.GetString(reader.GetOrdinal("Name")));
//读取Age
Log("" + reader.GetInt32(reader.GetOrdinal("Age")));
//读取Email
Log(reader.GetString(reader.GetOrdinal("Email")));
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void Log(string s)
{
Console.WriteLine("" + s);
}
private void CreatePassWard()
{
try
{
// passWord = new SqLiteHelper("data source=password.db");
passWord = new SqLiteHelper("password.db");
//创建名为table1的数据表
passWord.CreateTable("password", new string[] { "ID", "PW" }, new string[] { "TEXT", "TEXT" });
//插入两条数据
passWord.InsertValues("password", new string[] { "小三", "123456" });
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
passWord.CloseConnection();
}
}
private void ReadPassWardFromdb()
{
try
{
//连接数据库
// passWord = new SqLiteHelper("data source=password.db");
passWord = new SqLiteHelper("password.db");
//读取整张表
SQLiteDataReader reader = passWord.ReadFullTable("password");
if (reader.Read())
{
//读取ID与pw
richTextBox1.Text = reader.GetString(reader.GetOrdinal("ID"));
richTextBox3.Text = reader.GetString(reader.GetOrdinal("PW"));
}
passWord.CloseConnection();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
passWord.CloseConnection();
}
}
private void button1_Click(object sender, EventArgs e)
{
string Id = "";
string pw = "";
//连接数据库
// passWord = new SqLiteHelper("data source=password.db");
passWord = new SqLiteHelper("password.db");
//读取整张表
SQLiteDataReader reader = passWord.ReadFullTable("password");
if (reader.Read())
{
//读取ID
Id = reader.GetString(reader.GetOrdinal("ID"));
pw = reader.GetString(reader.GetOrdinal("PW"));
if (pw == richTextBox2.Text.Trim().ToString() && Id == richTextBox1.Text.Trim().ToString())
{
MessageBox.Show("用户名与密码正确：" + reader.GetString(0));
}
else
{
MessageBox.Show("用户名与密码错误：" + reader.GetString(0));
}
}
passWord.CloseConnection();
}
///
/// 修改密码
///
///
///
private void button2_Click(object sender, EventArgs e)
{
if (!flag)
{
richTextBox3.Visible = true;
label3.Visible = true;
flag = true;
return;
}
//连接数据库
try
{
//passWord = new SqLiteHelper("data source=password.db");
passWord = new SqLiteHelper("password.db");
passWord.UpdateValues("password", new string[] { "PW" }, new string[] { richTextBox3.Text.Trim().ToString() }, "ID", richTextBox1.Text.Trim().ToString(), "=", "ID","小四");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
passWord.CloseConnection();
}
}
}
}