并不是要介绍网上一搜一大片的Sqlite在Unity中的用法，而是想介绍下不一样的封装。另外对Unity和C#中的反射也并不熟练，所以难免疏漏。
Unity中使用Sqlite
所需文件
Mono.Data.Sqlite.dll
Mono.Data.dll
Sqlite3.dll （32位/64位）
前两个文件在 \Unity\Editor\Data\MonoBleedingEdge\lib\mono\2.0 这个目下可以找到
后一个文件Sqlite 可以在这儿下载 https://sourceforge.net/projects/sqlitebrowser/ 需要注意下载对应的32位或者64位
将上面的三个文件拷贝至文件夹 Asset\Plugins 下。如果是用在Android上，还需要一个 libsqlite3.so 文件，放在 Asset\Plugins\Android\ 下，文件可以在下面的链接的文章中下载到。http://blog.csdn.net/qinyuanpei/article/details/46812655#t1
不知道为啥编辑器没有自动添加引用，所以使用时记得添加下面的几个引用。
：unity`SqliteConnection' could not be found.
using Mono.Data.Sqlite;
：The type ornamespace name `Exception' could not be found.
using System;
：The type ornamespace name `SqliteDataReader' could not be found.
using System.IO;
简单使用
如果只是想简单的用用，下面的代码是一个使用示例。
来源：http://answers.unity3d.com/questions/743400/database-sqlite-setup-for-unity.html
string conn = "URI=file:" + Application.dataPath + "/PickAndPlaceDatabase.s3db"; //Path to database.
SqliteConnection dbconn;
dbconn = new SqliteConnection(conn);
dbconn.Open(); //Open connection to the database.
SqliteCommand dbcmd = dbconn.CreateCommand();
string sqlQuery = "SELECT value,name, randomSequence " + "FROM PlaceSequence";
dbcmd.CommandText = sqlQuery;
SqliteDataReader reader = dbcmd.ExecuteReader();
while (reader.Read())
{
int value = reader.GetInt32(0);
string name = reader.GetString(1);
int rand = reader.GetInt32(2);
Debug.Log( "value= "+value+" name ="+name+" random ="+ rand);
}
reader.Close();
reader = null;
dbcmd.Dispose();
dbcmd = null;
dbconn.Close();
dbconn = null;
}
封装 DbUtil (反射)
如何在Unity上使用用上Sqlite 在这里不做过多的讨论，因为上面的两个链接里已经有详细的描述了。这里讨论下另外的写法。
保存数据时，我并不希望每次保存数据时都去写一遍Sql，而是希望更简洁的操作。我不想去关心我是在操作那个类的数据类，里面有哪些字段 等等的封装。
比如创建两张不同的表：
dbUtil.CreateTable(new Pen());
dbUtil.CreateTable(new Person());
插入一条记录：
dbUtil.Insert(new Pen() { Id = 1, name = "钢笔1", color = "red", size = 1.123 });
插入链表：
dbUtil.InsertList(personList);
dbUtil.InsertList(penList);
不需要再去关心是哪个类，实体类有哪些字段等，就保存到数据库了。以前做Android开发的时候有很多开源框架可以使用，比如 xUtils 等。在Unity这用Sqlite似乎需求比较少，所以自己动手写个简单点的。用反射似乎效率会比较低，反射虽然慢，但对我们来说足以够快了。况且 数据库操作不都是放到另外的线程里去的么？
Column.cs
首先要完成上面的操作，重要的一点就是拼接Sql语句，那就要先拿到类的相关信息。Sqlite 支持四中类型，blob用的少，不管了。另外三个 int对应integer，string对应text，double对应real。代码如下：
namespace Liangddyy.Util
{
/// <summary>
/// 反射字段
/// </summary>
public class Column
{
//Column Value
private readonly MyProperty property;
public string columnName;
public Type columnType;
public Column(Type ColumnType, string ColumnName, object value)
{
this.columnType = ColumnType;
this.columnName = ColumnName;
if (ColumnType == typeof(string))
{
string v = Convert.ToString(value);
property = new MyProperty<string>();
((MyProperty<string>) property).SetValue(v);
}
else if (ColumnType == typeof(double))
{
double v = Convert.ToDouble(value);
property = new MyProperty<double>();
((MyProperty<double>) property).SetValue(v);
}
else if (ColumnType == typeof(int))
{
int v = Convert.ToInt32(value);
property = new MyProperty<int>();
((MyProperty<int>) property).SetValue(v);
}
}
public string TableType
{
get
{
if (IsPrimaryKey)
return "INTEGER PRIMARY KEY";
return To_TableType(columnType);
}
}
public bool IsPrimaryKey
{
// 转换小写
get
{
return (columnName.ToLower().StartsWith("id") || columnName.ToLower().StartsWith("_id")) &&
(columnType == typeof(int));
}
}
public object ColumnValue
{
get
{
if (property == null) return null;
if (columnType == typeof(double))
return ((MyProperty<double>) property).GetValue();
if (columnType == typeof(string))
return ((MyProperty<string>) property).GetValue();
if (columnType == typeof(int))
return ((MyProperty<int>) property).GetValue();
return null;
}
}
public string To_TableType(Type type)
{
if (type == typeof(double)) return ColType.REAL.ToString();
if (type == typeof(int)) return ColType.INTEGER.ToString();
if (type == typeof(string)) return ColType.TEXT.ToString();
throw new Exception("Wrong Type");
}
}
/// <summary>
/// 枚举数据库Sqlite支持的几种类型
/// </summary>
public enum ColType
{
INTEGER,
TEXT,
REAL,
BLOB
}
public class MyProperty
{
}
public class MyProperty<T> : MyProperty
{
private readonly bool _isValue;
private bool _changing;
private T _value;
public MyProperty()
{
#if UNITY_FLASH
_isValue = false;
#else
_isValue = typeof(T).IsValueType;
#endif
}
public MyProperty(T value)
: this()
{
_value = value;
}
public bool IsOfType(Type t)
{
return t == typeof(T);
}
public T GetValue()
{
return _value;
}
protected virtual bool IsValueDifferent(T value)
{
return !_value.Equals(value);
}
private bool IsClassDifferent(T value)
{
return !_value.Equals(value);
}
public virtual void SetValue(T value)
{
if (_changing)
return;
_changing = true;
bool changed;
if (_isValue)
changed = IsValueDifferent(value);
else
changed = ((value == null) && (_value != null)) ||
((value != null) && (_value == null)) ||
((_value != null) && IsClassDifferent(value));
if (changed)
_value = value;
_changing = false;
}
}
}
DbUtil.cs
注意事项写在后面。
namespace Liangddyy.Util
{
/// <summary>
/// 自己写的Sqlite封装类
/// </summary>
public class DbUtil
{
#if UNITY_ANDROID
private static string path = "URI=file:" + Application.dataPath;
#endif
#if UNITY_IPHONE
private static string path = "data source=" + Application.persistentDataPath;
#endif
#if UNITY_STANDALONE_WIN
private static readonly string path = "data source=" + Application.dataPath;
#endif
private static readonly string dbName = "/test01.db";
private static DbUtil dbUtil;
private SqliteConnection dbConnection;
private SqliteCommand dbCmd;
private SqliteTransaction dbTransaction;
private SqliteDataReader dbReader;
public static DbUtil getInstance()
{
if (dbUtil == null)
dbUtil = new DbUtil(path + dbName);
return dbUtil;
}
private DbUtil(string connectionStr)
{
try
{
dbConnection = new SqliteConnection(connectionStr);
}
catch (Exception e)
{
Debug.LogError(e.Message);
}
}
public SqliteDataReader ExecuteQuery(string queryString)
{
dbCmd = dbConnection.CreateCommand();
dbCmd.CommandText = queryString;
dbReader = dbCmd.ExecuteReader();
return dbReader;
}
public int ExecuteSql(string sqlStr)
{
if (dbConnection.State == ConnectionState.Closed)
dbConnection.Open();
dbCmd = dbConnection.CreateCommand();
dbCmd.CommandText = sqlStr;
return dbCmd.ExecuteNonQuery();
}
private int ExecuteSql(SqliteCommand sqlCmd)
{
return dbCmd.ExecuteNonQuery();
}
public void CreateTable<T>(T arg)
{
this.ExecuteSql(GetCmdCreateTable(arg));
}
public void Insert<T>(T record)
{
dbCmd = dbConnection.CreateCommand();
this.ExecuteSql(GetCmdInsert<T>(record, dbCmd));
}
public void InsertList<T>(List<T> Records)
{
dbTransaction = dbConnection.BeginTransaction();
try
{
for (var i = 0; i < Records.Count; i++)
Insert(Records[i]);
dbTransaction.Commit();
}
catch (Exception)
{
dbTransaction.Rollback();
throw;
}
}
public void InsertArray<T>(T[] Records)
{
dbTransaction = dbConnection.BeginTransaction();
try
{
for (var i = 0; i < Records.Length; i++)
Insert(Records[i]);
dbTransaction.Commit();
}
catch (Exception)
{
dbTransaction.Rollback();
throw;
}
}
public void Update<T>(T arg)
{
dbCmd = dbConnection.CreateCommand();
this.ExecuteSql(GetCmdUpdate(arg, dbCmd));
}
/// <summary>
/// 关闭数据库连接 销毁连接
/// </summary>
public void CloseConnection()
{
//销毁Command
if (dbCmd != null)
dbCmd.Cancel();
dbCmd = null;
//销毁Reader
if (dbReader != null)
dbReader.Close();
dbReader = null;
//销毁Connection
if (dbConnection != null)
dbConnection.Close();
dbConnection = null;
}
/// <summary>
/// 更新的sql语句
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="arg">The argument.</param>
/// <param name="cmd">The command.</param>
/// <returns></returns>
private SqliteCommand GetCmdUpdate<T>(T arg, SqliteCommand cmd)
{
Type type = arg.GetType();
var TableName = type.Name;
Column[] Columns = GetColumnsByType(arg);
if ((Columns == null) || (Columns.Length < 1))
{
Debug.LogError("Type is Wrong");
return null;
}
Column key = null;
Column[] normal = null;
//Debug.Log("Now Insert:" + TableName);
var RowLength = Columns.Length;
normal = GetNormalColumn(Columns);
cmd.CommandText = "UPDATE " + TableName + " SET " + normal[0].columnName + " = @" + normal[0].columnName;
for (var i = 1; i < normal.Length; i++)
cmd.CommandText += "," + normal[i].columnName + " = @" + normal[i].columnName;
key = GetPrimaryColumn(Columns);
cmd.CommandText += " WHERE " + key.columnName + " = @" + key.columnName + ";";
for (var i = 0; i < RowLength; i++)
cmd.Parameters.Add(new SqliteParameter("@" + Columns[i].columnName, Columns[i].ColumnValue));
return cmd;
}
/// <summary>
/// 获取主键
/// </summary>
/// <param name="Columns">The columns.</param>
/// <returns></returns>
private Column GetPrimaryColumn(Column[] Columns)
{
foreach (var item in Columns)
if (item.IsPrimaryKey) return item;
return null;
}
/// <summary>
/// 获取普通字段
/// </summary>
/// <param name="Columns">The columns.</param>
/// <returns></returns>
private Column[] GetNormalColumn(Column[] Columns)
{
var tmp = new List<Column>();
foreach (var item in Columns)
if (!item.IsPrimaryKey)
tmp.Add(item);
return tmp.ToArray();
}
/// <summary>
/// 获取类的相关字段信息。
/// </summary>
/// <param name="arg">The argument.</param>
/// <returns></returns>
private Column[] GetColumnsByType<T>(T arg)
{
FieldInfo[] fieldsThis =
arg.GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
FieldInfo[] fieldsBase =
arg.GetType().BaseType.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
FieldInfo[] fields = new FieldInfo[fieldsBase.Length + fieldsThis.Length];
Array.Copy(fieldsBase, 0, fields, 0, fieldsBase.Length);
Array.Copy(fieldsThis, 0, fields, fieldsBase.Length, fieldsThis.Length);
int field_len = fields.Length;
if ((fields == null) || (field_len < 1))
return null;
Column[] tableType = new Column[field_len];
for (int i = 0; i < field_len; i++)
{
String Cur_Name = fields[i].Name;
Type Cur_Type = fields[i].FieldType;
var Value = fields[i].GetValue(arg);
tableType[i] = new Column(Cur_Type, Cur_Name, Value);
}
return tableType;
}
/// <summary>
/// 建表Sql
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="arg">The argument.</param>
/// <returns></returns>
private string GetCmdCreateTable<T>(T arg)
{
Type type = arg.GetType();
string TableName = type.Name;
Column[] columns = GetColumnsByType(arg);
if ((columns == null) || (columns.Length < 1))
{
Debug.LogError("Type is Wrong");
//todo 异常处理
return null;
}
Debug.Log("NowCreate:" + TableName);
string queryCreate = "CREATE TABLE IF NOT EXISTS " + TableName + "(" + columns[0].columnName + " " +
columns[0].TableType;
for (var i = 1; i < columns.Length; i++)
queryCreate += ", " + columns[i].columnName + " " + columns[i].TableType;
queryCreate += ");";
return queryCreate;
}
/// <summary>
/// 获取一条插入sql语句
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="record">The record.</param>
/// <param name="cmd">The command.</param>
/// <returns></returns>
private SqliteCommand GetCmdInsert<T>(T record, SqliteCommand cmd)
{
Type type = record.GetType();
string TableName = type.Name;
Column[] columns = GetColumnsByType(record);
if ((columns == null) || (columns.Length < 1))
{
Debug.LogError("Type is Wrong");
return null;
}
int RowLength = columns.Length;
cmd.CommandText = "INSERT INTO " + TableName + "(" + columns[0].columnName;
for (var i = 1; i < RowLength; i++)
cmd.CommandText += "," + columns[i].columnName;
cmd.CommandText += ") VALUES (@" + columns[0].columnName;
for (var i = 1; i < RowLength; i++)
cmd.CommandText += ",@" + columns[i].columnName;
cmd.CommandText += ");";
for (var i = 0; i < RowLength; i++)
cmd.Parameters.Add(new SqliteParameter("@" + columns[i].columnName, columns[i].ColumnValue));
return cmd;
}
}
}
注意事项
1 不同平台下数据库文件的路径不同，所以要判断一下。
#if UNITY_ANDROID
private static string path = "URI=file:" + Application.dataPath;
#endif
#if UNITY_IPHONE
private static string path = "data source=" + Application.persistentDataPath;
#endif
#if UNITY_STANDALONE_WIN
private static readonly string path = "data source=" + Application.dataPath;
#endif
2 获取当前类的字段信息
GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
获取父类的字段信息（BaseType）
arg.GetType().BaseType.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
主要注意的是：
BindingFlags.Public 只能拿到public字段，而往往我们写实体类时，都是私有属性，然后Get/Set 所以必须加上BindingFlags.NonPublic 才能获取私有属性。
3 拼接Sql语句时切忌直接用String 拼接。
否则可能会有下面类似的报错：
SqliteException: SQLite error Insufficient parameters supplied to the command ...
正确写法类似于下面或者上面贴出的代码中拼接Sql部分。
command.CommandText = "INSERT INTO [User] (UserPK ,Name ,Password ,Category ,ContactFK) VALUES ( @UserPK , @Name , @Password , @Category , @ContactFK)";
command.Parameters.Add(new SqliteParameter("@Name", "Has"));
...
优雅的使用
BaiduShurufa_2016-12-9_15-22-22
（截图是因为这里不必要的代码很长，这个代码又没有什么意思。）
建了三个类，为了区别，另外两个类属性一个是private，一个是public。（Get/Set隐藏了）。
随便绑定个脚本Start里放上下面的代码 测试一下
DbUtil dbUtil = DbUtil.getInstance();
dbUtil.CreateTable(new Person());//建表
dbUtil.CreateTable(new Pen());
dbUtil.Insert(new Pen() { Id = 1, name = "钢笔1", color = "red", size = 1.123 });//插入
dbUtil.Insert(new Person() { Id = 1, Name = "liangddyy", Email = "hehe" });
List<Pen> penList = new List<Pen>();
List<Person> personList = new List<Person>();
for (int i = 5; i < 20; i++)
{
Pen pen = new Pen() {Id = i, name = "钢笔1", color = "red", size = 1.123};
Person person = new Person() {Id = i, Name = "liang", Email = "你好"};
personList.Add(person);
penList.Add(pen);
}
dbUtil.InsertList(penList);//插入链表
dbUtil.InsertList(personList);
dbUtil.Update(new Person() { Id = 1, Name = "梁先生", Email = "这条记录被修改了哈哈" });
dbUtil.CloseConnection();
打开 Sqlite数据库文件
123
122
搞定。
另外，我用的Sqlite可视化工具是 Navicat Premium，各种数据库都能连接。神器。
需完善的地方
- 查询部分。因为DbModel还没写。
- 异常处理。这个不太擅长。
- SaveOrUpdate() 和SaveOrUpdateList() 方法。
- Android里面比较流行用注解的方式，C#貌似是用自定义特性么？总之是想实现通过标注的方式来获取字段的特征，如是否非空等或者说通过实体类自定义字段名等。
有时间再完善吧。
