entity-framework

问题 Has anyone used .NET Core with DB2 and EF Core? We've tried to find compatible drivers, but none seem to exist. Has anyone found a way to use DB2 with .NET Core 3.0? Thank you! 回答1: There is no core 3.0 or standard 2.1 support thanks to IBM's terrible .Net support. Supposedly an alpha driver will be available in March 2020 if you contact their support. You can some of the conversation at this link. 回答2: IBM have now released a new version 3.1.0.300 of IBM.EntityFrameworkCore on nuget that

问题 How do I find the DataType of Metadata.IProperty in Entity Framework Core? var tableType = _dbContext.Model.GetEntityTypes().First(c => c.GetTableName() == tableName); foreach (var property in tableType.GetProperties()) { var test = property.PropertyInfo.PropertyType.Name; Using property.PropertyInfo.PropertyType.Name , sometimes works, however for nullable objects it prints null. I am looking for a clean way to get data type. 回答1: The Type of the IProperty is represented by ClrType property.

问题 I have created a query that allows group messages based on the reference number and chose each group's latest record. var list = _context.Messages.Include(m => m.SenderId).Include(m => m.ReceiverId) .Where(m => m.Status != MessageStatus.Archived) .OrderByDescending(m => m.DateAdded) .GroupBy(m => m.Reference) .Select(g => g.OrderByDescending(m => m.DateAdded).FirstOrDefault()).ToList(); Can someone suggest how to convert this to EF Core? 来源： https://stackoverflow.com/questions/64836474/ef6

问题 I am building a .NET application for inserting data (an Excel add-in in fact), and I want to use an ORM for inserting data with automated versioning . Here's a worked example: User "John Doe" does the first data insertion (4 data points as per below example) At a later time, user "Albert" opens the interface, modifies one data point, and saves All 4 data points are processed; ORM flags the modified data as non-Current, adds the new data, updates version counter, changes validity dates columns

问题 I am building a .NET application for inserting data (an Excel add-in in fact), and I want to use an ORM for inserting data with automated versioning . Here's a worked example: User "John Doe" does the first data insertion (4 data points as per below example) At a later time, user "Albert" opens the interface, modifies one data point, and saves All 4 data points are processed; ORM flags the modified data as non-Current, adds the new data, updates version counter, changes validity dates columns

问题 I am building a .NET application for inserting data (an Excel add-in in fact), and I want to use an ORM for inserting data with automated versioning . Here's a worked example: User "John Doe" does the first data insertion (4 data points as per below example) At a later time, user "Albert" opens the interface, modifies one data point, and saves All 4 data points are processed; ORM flags the modified data as non-Current, adds the new data, updates version counter, changes validity dates columns

问题 I am building a .NET application for inserting data (an Excel add-in in fact), and I want to use an ORM for inserting data with automated versioning . Here's a worked example: User "John Doe" does the first data insertion (4 data points as per below example) At a later time, user "Albert" opens the interface, modifies one data point, and saves All 4 data points are processed; ORM flags the modified data as non-Current, adds the new data, updates version counter, changes validity dates columns

问题 Below is my SQL query that I'm looking to convert to LINQ query SELECT ProcessName, SUM(CASE WHEN Status = 'In-Progress' THEN 1 ELSE 0 END) As 'In-Progress', SUM(CASE WHEN Status = 'Success' THEN 1 ELSE 0 END) As 'Completed', Count(CASE WHEN status in ('In-Progress','Success') then 1 end) as Total FROM TableName GROUP BY ProcessName 回答1: The first part is easy. The SQL expression SUM(CASE WHEN condition THEN 1 ELSE 0 END) directly maps to the LINQ Sum(condition ? 1 : 0) . More interesting is

问题 this is my appsettings.json "ConnectionStrings": { "Circolari": "Server=abcde;Database=Circolari;Trusted_Connection=True;" } and this is my startup.cs public Startup(IConfiguration configuration, IHostingEnvironment env) { Configuration = configuration; IConfigurationBuilder configurationBuilder = new ConfigurationBuilder() .SetBasePath(env.ContentRootPath) .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true); Configuration = configurationBuilder.Build(); } // This method

问题 this is my appsettings.json "ConnectionStrings": { "Circolari": "Server=abcde;Database=Circolari;Trusted_Connection=True;" } and this is my startup.cs public Startup(IConfiguration configuration, IHostingEnvironment env) { Configuration = configuration; IConfigurationBuilder configurationBuilder = new ConfigurationBuilder() .SetBasePath(env.ContentRootPath) .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true); Configuration = configurationBuilder.Build(); } // This method