SQLite之C#版 System.Data.SQLite使用方法
SQLite简介
SQLite，是一款轻型的关系型数据库。它的设计目标是嵌入式。
它能够支持Windows/Linux/Unix等等主流的操作系统，同时能够跟很多程序语言相结合，比如 C++、C#、Object-C、PHP、Java等。
我是做手游开发的，在手机上使用SQLite 存储数据是很方便的。
System.Data.SqLite实践前期准备
- System.Data.SQLite 库下载，用于C#操作SQLite的dll文件。下载地址：http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki
- SQLite可视化工具下载，用于查看SQLite库数据表数据。下载地址：http://www.sqliteexpert.com/download.html
Tips:
1.根据自己的电脑是64bit或者32bit 以及使用的.NET Freamwork版本下载相应的的System.Data.SQLite。 下载解压文件如：
安装在指定目录后生成多个dll文件：
本文测试用的只有 System.Data.SQLite.dll 。对于SQLite库数据的增删改查已经足够用了。
2.SQLite数据库文件以.db为后缀。安装SQLite可视化工具后如图：
mydb是我测试用的数据库。
实践
对SQLite的增、删、改、查。
测试环境：VS2015 语言：C#
创建控制台新工程，引入System.D【文章来源：http://www.yidunidc.com/mg.html 原文提供 欢迎转载】ata.SQLite.dll 文件。
1.编写SQLite 操作类， 对SQLite数据操作进行封装为 SqLiteHelper，代码如下：
/// <summary>
/// SQLite 操作类
/// </summary>
class SqLiteHelper
{
/// <summary>
/// 数据库连接定义
/// </summary>
private SQLiteConnection dbConnection;
/// <summary>
/// SQL命令定义
/// </summary>
private SQLiteCommand dbCommand;
/// <summary>
/// 数据读取定义
/// </summary>
private SQLiteDataReader dataReader;
/// <summary>
/// 构造函数
/// </summary>
/// <param name="connectionString">连接SQLite库字符串</param>
public SqLiteHelper(string connectionString)
{
try
{
dbConnection = new SQLiteConnection(connectionString);
dbConnection.Open();
}catch(Exception e)
{
Log(e.ToString());
}
}
/// <summary>
/// 执行SQL命令
/// </summary>
/// <returns>The query.</returns>
/// <param name="queryString">SQL命令字符串</param>
public SQLiteDataReader ExecuteQuery(string queryString)
{
try
{
dbCommand = dbConnection.CreateCommand();
dbCommand.CommandText = queryString;
dataReader = dbCommand.ExecuteReader();
}catch(Exception e)
{
Log(e.Message);
}
return dataReader;
}
/// <summary>
/// 关闭数据库连接
/// </summary>
public void CloseConnection()
{
//销毁Commend
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;
}
/// <summary>
/// 读取整张数据表
/// </summary>
/// <returns>The full table.</returns>
/// <param name="tableName">数据表名称</param>
public SQLiteDataReader ReadFullTable(string tableName)
{
string queryString = "SELECT * FROM " + tableName;
return ExecuteQuery(queryString);
}
/// <summary>
/// 向指定数据表中插入数据
/// </summary>
/// <returns>The values.</returns>
/// <param name="tableName">数据表名称</param>
/// <param name="values">插入的数值</param>
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);
}
/// <summary>
/// 更新指定数据表内的数据
/// </summary>
/// <returns>The values.</returns>
/// <param name="tableName">数据表名称</param>
/// <param name="colNames">字段名</param>
/// <param name="colValues">字段名对应的数据</param>
/// <param name="key">关键字</param>
/// <param name="value">关键字对应的值</param>
/// <param name="operation">运算符：=,<,>,...，默认“=”</param>
public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues, string key, string value, string operation="=")
{
//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);
}
/// <summary>
/// 删除指定数据表内的数据
/// </summary>
/// <returns>The values.</returns>
/// <param name="tableName">数据表名称</param>
/// <param name="colNames">字段名</param>
/// <param name="colValues">字段名对应的数据</param>
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);
}
/// <summary>
/// 删除指定数据表内的数据
/// </summary>
/// <returns>The values.</returns>
/// <param name="tableName">数据表名称</param>
/// <param name="colNames">字段名</param>
/// <param name="colValues">字段名对应的数据</param>
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);
}
/// <summary>
/// 创建数据表
/// </summary> +
/// <returns>The table.</returns>
/// <param name="tableName">数据表名</param>
/// <param name="colNames">字段名</param>
/// <param name="colTypes">字段名类型</param>
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);
}
/// <summary>
/// Reads the table.
/// </summary>
/// <returns>The table.</returns>
/// <param name="tableName">Table name.</param>
/// <param name="items">Items.</param>
/// <param name="colNames">Col names.</param>
/// <param name="operations">Operations.</param>
/// <param name="colValues">Col values.</param>
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);
}
/// <summary>
/// 本类log
/// </summary>
/// <param name="s"></param>
static void Log(string s)
{
Console.WriteLine("class SqLiteHelper:::" + s);
}
}
Tips:1.别忘了引入：using System.Data.SQLite;
2.引入System.Data.SQLite.dll的同时，需要将 System.Data.SQLite.dll.config 文件放在同级目录下。否则加载dll文件时报错。
2.在工程主函数Main里面添加测试代码
class Program
{
private static SqLiteHelper sql;
static void Main(string[] args)
{
sql = new SqLiteHelper("data source=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","22","Zhang@163.com" });
sql.InsertValues("table1", new string[] { "2", "李四", "25", "Li4@163.com" });
//更新数据，将Name="张三"的记录中的Name改为"Zhang3"
sql.UpdateValues("table1", new string[] { "Name" }, new string[] { "ZhangSan" }, "Name", "Zhang3");
//删除Name="张三"且Age=26的记录,DeleteValuesOR方法类似
sql.DeleteValuesAND("table1", new string[] { "Name", "Age" }, new string[] { "张三", "22" }, 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")));
}
while (true)
{
Console.ReadLine();
}
}
static void Log(string s)
{
Console.WriteLine(""+s);
}
}
Tips:1.别忘了引入：using System.Data.SQLite;
vs2015有NuGet，vs2013默认没有这个插件。
System.Data.SQLite 可以在VS中直接通过NuGet获取到。
到此这篇关于SQLite之C#版 System.Data.SQLite使用方法的文章就介绍到这了,更多相关System.Data.SQLite内容请搜索海外IDC网以前的文章或继续浏览下面的相关文章希望大家以后多多支持海外IDC网！
【出处：http://www.1234xp.com/xgzq.html 网络转载请说明出处】