Maikebing.Data.Taos 是一个基于TDengine 的RESTful Connector构建的ADO.Net 提供程序。 它这将允许你通过.Net Core 访问TDengine数据库。Maikebing.EntityFrameworkCore.Taos 是一个TDengine 的 Entity Framework Core 的提供程序,用于你在使用EFCore访问TDengine,由于官方没有提供任何已编译可供Linux、Windows、MacOS的C++ Connector,要实现.Net Core 横跨三平台需要研读C++ Connector代码并在三个平台下进行测试。 与此同时又需要阅读ADO.Net 和EFCore 框架的代码, 压力巨大,因此我先使用 RESTful Connector 等官方发布三平台下经过测试的动态库后再重写ADO.Net,或者当我有时间拜读TDengine代码时可以考虑重写。
Maikebing.EntityFrameworkCore.Taos 1.0.13 现在已经发布,对Entity Framework Core 的实现已经完成, 另外, 你需要注意的是 , 这是一个时序数据库,不是关系型数据库,有很多关系型需求是会报错的,比如,按照官方要求 第一个字段必须是日期。
下面是最新版本的示例:
///Specify the name of the database
string database = "db_" + DateTime.Now.ToString("yyyyMMddHHmmss");
var builder = new TaosConnectionStringBuilder()
{
DataSource = "http://td.gitclub.cn/rest/sql",
DataBase = database,
Username = "root",
Password = "taosdata"
};
//Example for ADO.Net
using (var connection = new TaosConnection(builder.ConnectionString))
{
connection.Open();
Console.WriteLine("create {0} {1}", database, connection.CreateCommand($"create database {database};").ExecuteNonQuery());
Console.WriteLine("create table t {0} {1}", database, connection.CreateCommand($"create table {database}.t (ts timestamp, cdata int);").ExecuteNonQuery());
Console.WriteLine("insert into t values {0} ", connection.CreateCommand($"insert into {database}.t values ('{DateTime.Now.ToString("yyyy-MM-dd HH🇲🇲ss.ms")}', 10);").ExecuteNonQuery());
Console.WriteLine("insert into t values {0} ", connection.CreateCommand($"insert into {database}.t values ('{DateTime.Now.AddMonths(1).ToString("yyyy-MM-dd HH🇲🇲ss.ms")}', 20);").ExecuteNonQuery());
var cmd_select = connection.CreateCommand();
cmd_select.CommandText = $"select * from {database}.t";
var reader = cmd_select.ExecuteReader();
Console.WriteLine(cmd_select.CommandText);
Console.WriteLine("");
ConsoleTableBuilder.From(reader.ToDataTable()).WithFormat(ConsoleTableBuilderFormat.MarkDown).ExportAndWriteLine();
Console.WriteLine("");
Console.WriteLine("DROP TABLE {0} {1}", database, connection.CreateCommand($"DROP TABLE {database}.t;").ExecuteNonQuery());
Console.WriteLine("DROP DATABASE {0} {1}", database, connection.CreateCommand($"DROP DATABASE {database};").ExecuteNonQuery());
connection.Close();
}
//Example for Entity Framework Core
using (var context = new TaosContext(new DbContextOptionsBuilder()
.UseTaos(builder.ConnectionString).Options))
{
Console.WriteLine("EnsureCreated");
context.Database.EnsureCreated();
for (int i = 0; i < 10; i++)
{
var rd = new Random();
context.sensor.Add(new sensor() { ts = DateTime.Now.AddMilliseconds(i), degree = rd.NextDouble(), pm25 = rd.Next(0, 1000) });
}
Console.WriteLine("Saveing");
context.SaveChanges();
Console.WriteLine("");
Console.WriteLine("from s in context.sensor where s.pm25 > 0 select s ");
Console.WriteLine("");
var f = from s in context.sensor where s.pm25 > 0 select s;
var ary = f.ToArray();
ConsoleTableBuilder.From(ary.ToList()).WithFormat(ConsoleTableBuilderFormat.MarkDown).ExportAndWriteLine();
context.Database.EnsureDeleted();
}
Console.WriteLine("");
Console.WriteLine("Pass any key to exit....");
Console.ReadKey();
欲进一步了解 请前往 https://gitee.com/maikebing/Maikebing.EntityFrameworkCore.Taos
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