unity sqlite笔记

开发环境Unity2018.4 .net4.x

目标平台pc,android

引用库 从Editor\Data\Mono\lib\mono\2.0 导入 Mono.Data.Sqlite.dll (不需要System.Data.dll)

从网上下载sqlite.dll libsqlite3.so 或者https://github.com/feigebabata/unityTools/tree/master/SqliteTool/Plugins

1.链接数据库语句 new SqliteConnection("data source = "+databasePath);//databasePath是数据库文件路径 各平台通用

    IEnumerator Start()
    {
        string databasePath = Path.Combine(Application.persistentDataPath,"main.db");
        if(!File.Exists(databasePath))
        {
            string copyPath = Path.Combine(Application.streamingAssetsPath,"main.db");
            UnityWebRequest uwr = new UnityWebRequest(copyPath);
            uwr.downloadHandler = new DownloadHandlerFile(databasePath);
            yield return uwr.SendWebRequest();
            if(uwr.isHttpError || uwr.isNetworkError)
            {
                log(uwr.error);
            }

        }
        // string databasePath = Path.Combine(Application.streamingAssetsPath,"main.db");
        connection = new SqliteConnection("data source = "+databasePath);
        connection.Open();
        command = connection.CreateCommand();
        Debug.Log(connection.Database);
        // command.CommandText = "insert into Test2(Age,Name) values(66,'baba')";
        // command.ExecuteReader();
        // seletcAllTab();
        yield return null;
    }

2.数据库表总数:string sql = "select count(*) from sqlite_master";

3.表"Test1"是否存在

string sql = "select count(*) from sqlite_master where type='table' and name='Test1'";
command.CommandText = sql;
Debug.Log(command.ExecuteScalar());

4.表创建:"create table 表名(字段1 类型,字段2 类型)"

5.C# Sqlite类型转换  无需转换 这样写也可以: "create table Data2(Name String,ID Int32)"

    string CS2DB(Type type)
    {
        string result = "Text";
        if(type==typeof(Int32))
        {
            result = "Int";
        }
        else if (type == typeof(String))
        {
            result = "Text";
        }
        else if (type == typeof(Single))
        {
            result = "FLOAT";
        }
        else if (type == typeof(Boolean))
        {
            result = "Bool";
        }
        return result;
    }

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6.删除表"Test2": string sql = "drop table Test2";

7.添加数据:"insert into 表名(字段1,字段2) values(数据1,数据2)"

8.更新数据:"update 表名 set 更新字段1=更新数据1 where 字段2=数据2"

9.删除数据:"delete from 表名 where 字段1=数据2"

10.查询数据:"select * from 表名 where 字段1=数据1"

    void Select(string _table)
    {
        string sql = $"select * from {_table}";
        log(sql);
        command.CommandText = sql;
        reader = command.ExecuteReader();
        StringBuilder vals_sb = new StringBuilder();
        while(reader.Read())
        {
            for (int i = 0; i < reader.FieldCount; i++)
            {
                vals_sb.AppendFormat("{0}:{1},",reader.GetName(i),reader.GetValue(i));
            }
            log(vals_sb.ToString());
            vals_sb.Clear();
        }
        command.Dispose();
    }