To match the data types of columns in the database and in the class

Question

To match the data types of columns in the database and in the class

jhon65496 opened this issue 8 months ago · comments

Question: what types of columns should I use in the database and in the class for the correct operation of the application?

Project: https://github.com/jhon65496/TypeDataCnsl01

Used by:

Console .NET Framework;
EF6. Framework;
DB: SQLite;
System.Data.SQLite.

There is a problem with the columns IndexValue, Discount. The goal is to get data from the database and perform calculations.

If:

in the database, the columns IndexValue, Discount are of type DECIMAL(10, 5),;
in the Index class, the fields IndexValue, Discount are of type string.

then there are no problems and I get the data.

If

in the database, the columns IndexValue, Discount are of type DECIMAL(10, 5);
in the Index class, the fields IndexValue, Discount are of type decimal.

I get an error when debugging.

Error:

The recipient of the call has created an exception

The error occurs on the line

var items = indexesRepository.Items.toArray();

in the Load Data() method in the `IndexesViewModel' class.

public class IndexesViewModel
{   
    // ...
    // Code
    // ...
    
    public void LoadData()
    {         
        var items = indexesRepository.Items.ToArray();
        Indexes = new ObservableCollection<Index>(items);
    }
}

Code

Index class:

[Table("Indexes")]
public class Index 
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    // decimal
    // float        
    public decimal IndexValue { get; set; }
    public decimal Discount { get; set; }        
}

DbContextIndexes:

public class DbContextIndexes : DbContext
{
    static SQLiteConnection sqliteConnection;
    
    public DbContextIndexes() : base("DefaultConnection")
    {
    }

    public DbSet<Index> Indexes { get; set; }
}

IndexesRepository:

class IndexesRepository 
{
    private readonly DbSet<Index> _Set;
    DbContextIndexes _db;

    public IndexesRepository(DbContextIndexes db)
    {
        _db = db;
        _Set = _db.Set<Index>();
    }

    private IQueryable<Index> items;

    public virtual IQueryable<Index> Items
    {
        get
        {
            items = _Set;
            return items;
        }
        set
        {
            items = value;
        }
    }
}

IndexesViewModel:

public class IndexesViewModel
{   
    IndexesRepository indexesRepository;
    
    DbContextIndexes DataContextApp;

    public IndexesViewModel()
    {
        this.DataContextApp = new DbContextIndexes();
        indexesRepository   = new IndexesRepository(this.DataContextApp);

        LoadData();
    }

    private ObservableCollection<Index> indexes;

    public ObservableCollection<Index> Indexes
    {
        get { return indexes; }
        set 
        {
            indexes = value;                
        }
    }

    public void LoadData()
    {         
        var items = indexesRepository.Items.ToArray(); // <== Тут ошибка !!!
        Indexes = new ObservableCollection<Index>(items);
    }
}

SQL indexes:

CREATE TABLE "Indexes" 
(
	"Id"	INTEGER UNIQUE,
	"Name"	VARCHAR NOT NULL,
	"IndexValue"	DECIMAL(10, 5),
	"Discount"	DECIMAL(10, 5),
	"Description"	TEXT,
	PRIMARY KEY("Id" AUTOINCREMENT)
);

packages.config:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="EntityFramework" version="6.4.4" targetFramework="net48" />
  <package id="Stub.System.Data.SQLite.Core.NetFramework" version="1.0.118.0" targetFramework="net48" />
  <package id="System.Data.SQLite" version="1.0.118.0" targetFramework="net48" />
  <package id="System.Data.SQLite.Core" version="1.0.118.0" targetFramework="net48" />
  <package id="System.Data.SQLite.EF6" version="1.0.118.0" targetFramework="net48" />
  <package id="System.Data.SQLite.Linq" version="1.0.118.0" targetFramework="net48" />
</packages>

App.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
	<connectionStrings>
    <add name="DefaultConnection" connectionString="Data Source=dbAppIndexes.db" providerName="System.Data.SQLite" />
  </connectionStrings>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8" />
  </startup>
  <entityFramework>
    <providers>
		<provider invariantName="System.Data.SQLite" type="System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6" />
      <!--<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />-->
      <provider invariantName="System.Data.SQLite.EF6" type="System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6" />
    </providers>
  </entityFramework>
  <system.data>
    <DbProviderFactories>
      <remove invariant="System.Data.SQLite.EF6" />
      <add name="SQLite Data Provider (Entity Framework 6)" invariant="System.Data.SQLite.EF6" description=".NET Framework Data Provider for SQLite (Entity Framework 6)" type="System.Data.SQLite.EF6.SQLiteProviderFactory, System.Data.SQLite.EF6" />
    <remove invariant="System.Data.SQLite" /><add name="SQLite Data Provider" invariant="System.Data.SQLite" description=".NET Framework Data Provider for SQLite" type="System.Data.SQLite.SQLiteFactory, System.Data.SQLite" /></DbProviderFactories>
  </system.data>
</configuration>

Screenshot #1:

Screenshot #2:

Update-1

It's working.
Replaced the comma , with a period ..

What is the point?

Can I store data in a database only with a semicolon?
can I not store data in a database ?
Which types should I choose to store the IndexValue and Discount fields.

Update-2. Added: `CultureInfo'.

Result: it doesn't work

Does not work.
Project: https://github.com/jhon65496/TypeDataCnsl01/tree/CultureInfo01

I downloaded the Sqlite application from the official website.
I created a SQLLite database using an SQL query.
I have created an application.
In the application, I did not create the code used by CultureInfo .

Added in Main() in program.cs:

var cultureInfo = new CultureInfo("ru-RU");
CultureInfo.DefaultThreadCurrentCulture = cultureInfo;
CultureInfo.DefaultThreadCurrentUICulture = cultureInfo;

Full code

class Program
{
    static void Main(string[] args)
    {
        var cultureInfo = new CultureInfo("ru-RU");
        CultureInfo.DefaultThreadCurrentCulture = cultureInfo;
        CultureInfo.DefaultThreadCurrentUICulture = cultureInfo;

        IndexesViewModel indexesViewModel = new IndexesViewModel();
    }
}

Error text

Message = The recipient of the call has created an exception.

Internal exception 1:
FormatException: The input string had an incorrect format.

The full text of the error

System.Reflection.TargetInvocationException
  HResult=0x80131604
  Сообщение = Адресат вызова создал исключение.
  Источник = mscorlib
  Трассировка стека:
   в System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   в System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   в System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   в System.Data.Entity.Core.Common.Internal.Materialization.Shaper.ErrorHandlingValueReader`1.GetTypedValueDefault(DbDataReader reader, Int32 ordinal)
   в System.Data.Entity.Core.Common.Internal.Materialization.Shaper.ErrorHandlingValueReader`1.GetValue(DbDataReader reader, Int32 ordinal)
   в System.Data.Entity.Core.Common.Internal.Materialization.Shaper.HandleEntityAppendOnly[TEntity](Func`2 constructEntityDelegate, EntityKey entityKey, EntitySet entitySet)
   в System.Data.Entity.Core.Common.Internal.Materialization.Coordinator`1.ReadNextElement(Shaper shaper)
   в System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.SimpleEnumerator.MoveNext()
   в System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
   в System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   в System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)

  Изначально это исключение было создано в этом стеке вызовов: 
    [Внешний код]

Внутреннее исключение 1:
FormatException: Входная строка имела неверный формат.

Arthur Vickers · Answer 1 · Wed Dec 13 2023 18:40:49 GMT+0800 (China Standard Time)

This issue has been closed because EF6 is no longer being actively developed. We are instead focusing on stability of the codebase, which means we will only make changes to address security issues. See the repo README for more information.