C#系 SQLite4Unity的介绍

Posted 2021-03-29 猿媛大本营

为什么要记录这一篇呢？使用过Unity的猿媛们可能知道，Unity使用的.net框架一般比较老，比如说Unity5.6.3使用的是.net3.5Framework 导致有很多高效的库无法使用，比如将汉字转笔画或者转拼音的一些库就无法使用。这让我在项目开发中很抓狂。为了能在Unity项目中高效的使用SQLite数据库，经过各种对比，此插件更胜一筹。特此记录一下来分享给各位猿媛！（不要问我为什么要在Unity 项目中使用SQLite,因为软件是不联网的，又要有很多数据的支撑）

https://github.com/robertohuertasm/SQLite4Unity3d

下载完成后将按照下图中的路径找到Plugins目录和SQLite 导入到项目的Assets目录下

SQLite文件是对底层的一些封装，在后续操作中我们只需要在SQLite基础上进行操作即可

另外一个操作就是将DataService.cs导入到工程，这个操作其实是不一定是必要的，根据自己喜好。

此文件中定义了一些基础操作，我们可以直接利用

具体代码如下：

using SQLite4Unity3d;using System.Collections;using System.Collections.Generic;using UnityEngine;using System.IO;
public class Sqlite3BaseTable{ [PrimaryKey, AutoIncrement] public int Id { get; set; } public Sqlite3BaseTable() {
 }}
public class DataService{ private SQLiteConnection _connection;
 public DataService(string DatabaseName) {
#if UNITY_EDITOR var dbPath = string.Format(@"Assets/StreamingAssets/DB/{0}", DatabaseName); if (!Directory.Exists(@"Assets/StreamingAssets/DB/")) { Directory.CreateDirectory(@"Assets/StreamingAssets/DB/"); UnityEditor.AssetDatabase.Refresh(); }#else // check if file exists in Application.persistentDataPath var filepath = string.Format("{0}/{1}", Application.persistentDataPath, DatabaseName);
 if (!File.Exists(filepath)) { Debug.Log("Database not in Persistent path"); // if it doesn't -> // open StreamingAssets directory and load the db ->
#if UNITY_android var loadDb = new WWW("jar:file://" + Application.dataPath + "!/assets/" + DatabaseName); // this is the path to your StreamingAssets in android while (!loadDb.isDone) { } // CAREFUL here, for safety reasons you shouldn't let this while loop unattended, place a timer and error check // then save to Application.persistentDataPath File.WriteAllBytes(filepath, loadDb.bytes);#elif UNITY_ios var loadDb = Application.dataPath + "/Raw/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);#elif UNITY_WP8 var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);
#elif UNITY_WINRT var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath); #elif UNITY_STANDALONE_OSX var loadDb = Application.dataPath + "/Resources/Data/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);#else var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);
#endif
 Debug.Log("Database written"); }
 var dbPath = filepath;#endif _connection = new SQLiteConnection(dbPath, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.Create); Debug.Log("Final PATH: " + dbPath); }
 public void CreateTable<T>() { _connection.DropTable<T>(); _connection.CreateTable<T>(); } /// <summary> /// 插入多条数据到表中 /// </summary> /// <param name="objects"></param> /// <returns>插入到表中数据额条数</returns> public int InsertDataToTable(IEnumerable objects) { return _connection.InsertAll(objects); }
 /// <summary> /// 插入一条数据到表中 /// </summary> /// <param name="obj"></param> /// <returns>插入到表中数据额条数</returns> public int InsertDataToTable<T>(T obj) where T:Sqlite3BaseTable { return _connection.Insert(obj); }
 public T GetRowById<T>(int id) where T:Sqlite3BaseTable,new() { //var ret = from x in _connection.Table<T>() // where x.Id == id // select x; //return ret.FirstOrDefault(); return _connection.Table<T>().Where(x => x.Id == id).FirstOrDefault(); }
 /// <summary> /// 删除表 /// </summary> /// <typeparam name="T"></typeparam> public void DropTable<T>() { _connection.DropTable<T>(); }
 public IEnumerable<T> GetAllRows<T>() where T:Sqlite3BaseTable,new() { return _connection.Table<T>(); }}

DataService 可以帮助我们创建和数据库操纵的链接，以及其他操作

例如创建数据库的操作

public void CreateTable<T>(){    //删除数据库 _connection.DropTable<T>();    //创建数据库 _connection.CreateTable<T>();}

插入多条数据的操作

/// <summary>/// 插入多条数据到表中/// </summary>/// <param name="objects"></param>/// <returns>插入到表中数据额条数</returns>public int InsertDataToTable(IEnumerable objects){ return _connection.InsertAll(objects);}

插入一条数据

/// <summary>/// 插入一条数据到表中/// </summary>/// <param name="obj"></param>/// <returns>插入到表中数据额条数</returns>public int InsertDataToTable<T>(T obj) where T:Sqlite3BaseTable{ return _connection.Insert(obj);}

通过Id 的带一条数据

下面展示了两种操作数据的方式 ，在实际操作中任选其一

public T GetRowById<T>(int id) where T:Sqlite3BaseTable,new(){    //使用linq 操作数据库 var ret = from x in _connection.Table<T>() where x.Id == id select x; return ret.FirstOrDefault();    //使用lambda 表达式 return _connection.Table<T>().Where(x => x.Id == id).FirstOrDefault();}

删除表的操作

/// <summary>/// 删除表/// </summary>/// <typeparam name="T"></typeparam>public void DropTable<T>(){ _connection.DropTable<T>();}

得到所有的条目数据

public IEnumerable<T> GetAllRows<T>() where T:Sqlite3BaseTable,new(){ return _connection.Table<T>();}

以上针对与数据库的操作都支持Linq ,在此篇文章中不在赘述。可参考 通过Id 的带一条数据的操作

从其构造函数中可以看出，他支持多个平台，ANDROID，iOS,WP8,Window，并且它的数据库文件在Assets/StreamingAssets/DB 目录下，如果在创建的时候目录不存在，则会帮猿媛们创建对应的目录

 public DataService(string DatabaseName) {
#if UNITY_EDITOR var dbPath = string.Format(@"Assets/StreamingAssets/DB/{0}", DatabaseName); if (!Directory.Exists(@"Assets/StreamingAssets/DB/")) { Directory.CreateDirectory(@"Assets/StreamingAssets/DB/"); UnityEditor.AssetDatabase.Refresh(); }#else // check if file exists in Application.persistentDataPath var filepath = string.Format("{0}/{1}", Application.persistentDataPath, DatabaseName);
 if (!File.Exists(filepath)) { Debug.Log("Database not in Persistent path"); // if it doesn't -> // open StreamingAssets directory and load the db ->
#if UNITY_ANDROID var loadDb = new WWW("jar:file://" + Application.dataPath + "!/assets/" + DatabaseName); // this is the path to your StreamingAssets in android while (!loadDb.isDone) { } // CAREFUL here, for safety reasons you shouldn't let this while loop unattended, place a timer and error check // then save to Application.persistentDataPath File.WriteAllBytes(filepath, loadDb.bytes);#elif UNITY_IOS var loadDb = Application.dataPath + "/Raw/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);#elif UNITY_WP8 var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);
#elif UNITY_WINRT var loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath); #elif UNITY_STANDALONE_OSX var loadDb = Application.dataPath + "/Resources/Data/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS // then save to Application.persistentDataPath File.Copy(loadDb, filepath);#elsevar loadDb = Application.dataPath + "/StreamingAssets/" + DatabaseName; // this is the path to your StreamingAssets in iOS// then save to Application.persistentDataPathFile.Copy(loadDb, filepath);
#endif
 Debug.Log("Database written"); }
 var dbPath = filepath;#endif _connection = new SQLiteConnection(dbPath, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.Create); Debug.Log("Final PATH: " + dbPath); }

SQlite4Unity的插件是不是很强大！由于篇幅较长，SQLite的介绍先到这里，下一篇我们介绍SQlite4Unity的使用