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I can query mysql DB but not save changes to it

I had created a system using Visual Studio 2015 with a SQLServer database, i could query the DB but not save changes to it. So i created the database inside Visual Studio. I now tried to create the database in MySQL workbench and have the same issue. I switched to mysql as i was unsure if i had correctly installed My SQL Server, i have definately installed mysql properly as i have used it for projects in Java.
I created the database using a code first technique and this worked fine. Any ideas?
Connection String from appsettings
"DataAccessMySqlProvider": "server=localhost;port=3306;database=rentalsdb;userid=root;password=******"
In Startup.cs
var sqlConnectionString = Configuration.GetConnectionString("DataAccessMySqlProvider");
services.AddMvc();
services.AddDbContext<RentalsDbContext>(options =>
options.UseMySQL(
sqlConnectionString,
b => b.MigrationsAssembly("RentalsRated.Web")));
services.AddDbServiceDependencies(sqlConnectionString);
In my repo then
public bool CreateUser(UserAccount user)
{
if (user != null)
{
try
{
_Context.UserAccounts.Add(user);
_Context.Entry(user).State = EntityState.Modified;
_Context.SaveChanges();
return true;
}
catch ....
I can see the right variables come to here. It all worked fine with the database in visual studios server explorer.
Thanks!
IndexOutOfRangeException: Index was outside the bounds of the array.
The Stack trace: at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(Tuple2 parameters)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IReadOnlyList1 entriesToSave)...
UPDATE: Works when i comment out my data that is being passed as Byte[].

Root cause:
Password and salt fields are defined as blobs. Change the type of the password and salt fields to one of the string types instead.
Masking issue:
You were changing the state of the entity to Modifed right after adding it to the table which might corrupt the internal state of the context.
MSDN is recommending two different ways of adding new entity to the context
https://msdn.microsoft.com/en-us/library/jj592676(v=vs.113).aspx
1) By adding the entity directly to the table.
using (var context = new BloggingContext())
{
var blog = new Blog { Name = "ADO.NET Blog" };
context.Blogs.Add(blog);
context.SaveChanges();
}
2) By changing the state of the entity to Added
using (var context = new BloggingContext())
{
var blog = new Blog { Name = "ADO.NET Blog" };
context.Entry(blog).State = EntityState.Added;
context.SaveChanges();
}

How to configure an oracle database in apache ignite .NET

I'm trying to configure the write-through and read-through properties of apache Ignite with an Oracle database. I searched in many places like the Ignite oficial documentation, also in the ignite examples on GitHub,
but there isn't much information or examples coded in C# that is the lenguaje in which I'm developing my app.
What I want is to retrieve from a persistent store (in this case an Oracle database), an specific data in the cache (Ignite) that is not already loaded. In a similar way, I need all my changes on the cache to be reflected on the database.
I tied to create and spring.xml with the configuration of the database (ip, port, username, pass, database), but I can't make it work if that is the way it should be done.
Thanks in advance and sorry for my english.

1) Implement ICacheStore interface (or inherit CacheStoreAdapter helper class)
public class OracleStore : CacheStoreAdapter
{
public override object Load(object key)
{
using (var con = new OracleConnection
{
ConnectionString = "User Id=<username>;Password=<password>;Data Source=<datasource>"
})
{
con.Open();
var cmd = con.CreateCommand();
cmd.CommandText = "SELECT * FROM MyTable WHERE ID=#id";
cmd.Parameters.Add("#id", OracleType.Int32);
cmd.Parameters["#id"].Value = key;
using (var reader = cmd.ExecuteReader())
{
// Read data, return as object
}
}
}
public override void Write(object key, object val)
{
oracleDb.UpdateRow(key, val);
}
public override void Delete(object key)
{
oracleDb.DeleteRow(key);
}
}
2) Implement store factory:
public class OracleStoreFactory : IFactory<OracleStore>
{
public OracleStore CreateInstance()
{
return new OracleStore();
}
}
3) Configure cache to use store:
using (var ignite = Ignition.Start())
{
var cacheCfg = new CacheConfiguration
{
ReadThrough = true,
WriteThrough = true,
KeepBinaryInStore = false, // Depends on your case
CacheStoreFactory = new OracleStoreFactory()
};
var cache = ignite.CreateCache<int, MyClass>(cacheCfg);
cache.Get(1); // OracleStore.Load is called.
}
Documentation for Ignite.NET (in C#): https://apacheignite-net.readme.io/docs/persistent-store
C# examples are available in a full download package: https://ignite.apache.org/download.cgi#binaries (click apache-ignite-fabric-1.9.0-bin.zip, download, unzip, open platforms\dotnet\examples\Apache.Ignite.Examples.sln)
Blog post explaining cache store implementation in C#:
https://ptupitsyn.github.io/Entity-Framework-Cache-Store/
Working with Oracle DB in .NET: Connecting to Oracle Database through C#?

Retrieving SQL Generated by Entity Framework Core

I'm trying to retrieve the raw SQL generated by Entity Framework for the following LINQ query:
pagedItemResults = from firstItem in dbData.Accession
join secondItem in pagedRowNumberResults
on firstItem.AccessionNumber equals secondItem
select new PaginationResultRow
{
Number = firstItem.AccessionNumber,
ID = firstItem.AccessionId,
Name = firstItem.AcquisitionType.Name,
Description = firstItem.Description
};
Although it may be extremely simple and similar to the other answers already out there for previous versions of EF, I've had no luck and found nothing online.. any ideas??

You can turn on logging by implementing ILoggerProvider. See details in documentation.
You only need to register the logger with a single context instance. Once you have registered it, it will be used for all other instances of the context in the same AppDomain.
using (var db = new BloggingContext())
{
var serviceProvider = db.GetInfrastructure<IServiceProvider>();
var loggerFactory = serviceProvider.GetService<ILoggerFactory>();
loggerFactory.AddProvider(new MyLoggerProvider());
}
You can also define categories what you want to log.
private static string[] _categories =
{
typeof(Microsoft.Data.Entity.Storage.Internal.RelationalCommandBuilderFactory).FullName,
typeof(Microsoft.Data.Entity.Storage.Internal.SqlServerConnection).FullName
};

You can log tsql generated to output window by :
Microsoft.Extensions.Logging.Debug
First, get it from Nuget, then in your context, you must define a LoggerFactory.
After that, use it in OnConfiguring in your context.
public static readonly Microsoft.Extensions.Logging.LoggerFactory _loggerFactory =
new LoggerFactory(new[] {
new Microsoft.Extensions.Logging.Debug.DebugLoggerProvider()
});
optionsBuilder.UseLoggerFactory(_loggerFactory);

I really like MiniProfiler, see http://miniprofiler.com/. Short of something like this, I would say you'd have to use a profiler on the actual database.

run a primitive mycouch query

I'm new to couchdb and mycouch. I'm trying to implement a very simple query, I just want to get the results of a view and save it into my DTO class.
My couchdb query works, when I query it manually via HTTP:
http://localhost:5984/mydb/_design/tshirts/_view/getAllTshirts
However, when I try running it from my app using mycouch, I can't get to run it. My current query:
using MyCouch.Requests;
using MyCouch.Responses;
// (...)
using (var client = new Client("http://localhost:5984/samples")) {
var query = new QueryViewRequest("getAllTshirts");
ViewQueryResponse<TShirt[]> result = await client.Views.QueryAsync<TShirt[]>(query);
Console.WriteLine (result);
}
For some reason, it won't find the Client class. I found an example where Client is used on github, as you can see, I'm using all the MyCouch related namespaces as in the example.
I also tried using MyCouchStore instead:
using (var store = new MyCouchStore("http://localhost:5984/", "samples")) {
var query = new QueryViewRequest("getAllTshirts");
ViewQueryResponse<TShirt[]> result = await store.Views.QueryAsync<TShirt[]>(query);
Console.WriteLine (result);
}
However, the store doesn't contain any property named Views.
Any ideas how to query my view using MyCouch?

This is what I do, with the MyCouchStore
using (var store = new MyCouchStore("http://user:password#localhost:5984", "samples")) {
var query = new Query("tshirts", "getAllTshirts");
var rows = store.QueryAsync<TShirt>(query).Result;
}

Apparantely, the documentation was not up to date. The constructor requires now 2 arguments, the second being an optional bootstrapper. This worked for me:
var client = new Client("http://localhost:5984/samples", null)

Best practice to create (on demand) SQL Server 2008 Express databases in C#?

The purpose is to handle the user's data (you can call them project, document, file, or whatever) in a brand new SQL Server 2008 Express database. The data are expected to occupy much less space than the 4GB available with the express edition (which is also free to distribute).
E.g., each time the user selects File->New command, a new empty database will be created at the specified location. On the other hand, a similar command, File->Open must provide support to retrieve the list of the databases to select one for opening.
So, the following issues must be resolved:
a) The application must be able to create the connection string and attach the database to SQL Server 2008 Express through code (C#)
b) The application must be able to retrieve (again through code) a list with all the available databases, to give the user a chance to select one to open.
I think it would be helpful to have a template database in resources and copy it in the location specified by the user.
Do you think it is a working solution? Do you have any suggestions?

There's lots you can do with Sql Server Management Objects (SMO):
// Add a reference to Microsoft.SqlServer.Smo
// Add a reference to Microsoft.SqlServer.ConnectionInfo
// Add a reference to Microsoft.SqlServer.SqlEnum
using Microsoft.SqlServer.Management.Smo;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Data;
public class SqlServerController
{
private Server m_server = null;
public SqlServerController(string server)
{
m_server = new Server(server);
}
public void AttachDatabase(string database, StringCollection files,
AttachOptions options)
{
m_server.AttachDatabase(database, files, options);
}
public void AddBackupDevice(string name)
{
BackupDevice device = new BackupDevice(m_server, name);
m_server.BackupDevices.Add(device);
}
public string GetServerVersion(string serverName)
{
return m_server.PingSqlServerVersion(serverName).ToString();
}
public int CountActiveConnections(string database)
{
return m_server.GetActiveDBConnectionCount(database);
}
public void DeleteDatabase(string database)
{
m_server.KillDatabase(database);
}
public void DetachDatabase(string database, bool updateStatistics,
bool removeFullTextIndex)
{
m_server.DetachDatabase(database, updateStatistics, removeFullTextIndex);
}
public void CreateDatabase(string database)
{
Database db = new Database(m_server, database);
db.Create();
}
public void CreateTable(string database, string table,
List<Column> columnList, List<Index> indexList)
{
Database db = m_server.Databases[database];
Table newTable = new Table(db, table);
foreach (Column column in columnList)
newTable.Columns.Add(column);
if (indexList != null)
{
foreach (Index index in indexList)
newTable.Indexes.Add(index);
}
newTable.Create();
}
public Column CreateColumn(string name, DataType type, string #default,
bool isIdentity, bool nullable)
{
Column column = new Column();
column.DataType = type;
column.Default = #default;
column.Identity = isIdentity;
column.Nullable = nullable;
return column;
}
public Index CreateIndex(string name, bool isClustered, IndexKeyType type,
string[] columnNameList)
{
Index index = new Index();
index.Name = name;
index.IndexKeyType = type;
index.IsClustered = isClustered;
foreach (string columnName in columnNameList)
index.IndexedColumns.Add(new IndexedColumn(index, columnName));
return index;
}
}

An alternate solution is to use SQLite rather than SQL Express. You can even continue to use ADO.NET if you use this solution. SQLite databases are simply files, and your connection strings can refer to the file path. When a user wants to open their file, they can select an actual file.

I get the impression that this database will live locally on user's machine. If that's the case, sql server express is not usually a good database choice. It's a server-class engine rather than a desktop or in process engine. Instead, there are a number of good in process engines you can use: Sql Server Compact Edition, Sqlite (as mentioned by Jacob) or even Access.

If you believe SQL Server Express 2008 is the right choice (sqllite does seem to fit better though), I would look at using User Instances which will allow non-administrators to add databases from files as you describe.

This article shows how to create a new database, and attach it to a SQL Server database instance:
How to: Attach a Database File to SQL Server Express
http://msdn.microsoft.com/en-us/library/ms165673.aspx
These article shows how to manage the attaching and detaching of existing databases:
http://msdn.microsoft.com/en-us/library/ms190794.aspx
http://www.databasejournal.com/features/mssql/article.php/2224361/Attaching-and-Detaching-Databases-on-SQL-Server.htm

For the following connection string for SQL Server 2008 R2.
<connectionstring>Data Source=.\SQLEXPRESS;Initial Catalog=MyDatabase;Integrated Security=True;Pooling=True</connectionstring>
you can do
var connectionString = new SqlConnectionStringBuilder(connectionString);
var serverConnection = new ServerConnection("DatabaseInstanceName in server");
var serverInstance = new Server(serverConnection);
if (serverInstance.Databases.Contains(connectionString.InitialCatalog))
serverInstance.KillDatabase(connectionString.InitialCatalog);
var db = new Database(serverInstance, connectionString.InitialCatalog);
try
{
db.Create();
}
catch (SqlException ex)
{
throw;
}
Thanks to Mr. Harvey for pointing the right direction. Although in my case, I have to make these small changes. Because, I use the windows authentication.