Consider the following code, where dbContext is a SQL Server database context and Examples is a DbSet: The first line works as expected and is converted to SQL in the following manner: However, the second line first fetches all rows and applies the Take operator afterwards. Why is that? Since I am using expressions to build a dynamic lambda I
Tag: c#
How to check if a specific data exist in a text file before insert it to SQL database table?
I have a Employee text file employee.txt which has some data in it. For instance: I want to read the file and get the empId from it and pass it to a function to check if that empId already exists in the SQL database table. Here’s my function: How do I get the empId from the file? And how to
Set Sql to Single User mode From C# and Create Admin User
I have a c# winform application which connects to a database and read data. This database is used by another app also. I just executed a query from my app to read some data. I don’t have the user …
Seeding a table with Foreign key
I encountered a problem where I cant seed an SQL script since it has a foreign key constraint, I tried context.SaveChanges() but it isn’t working. Is there any way how this can be done? protected …
Select statement: Invalid column name, in C# using Dapper [closed]
Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers. Closed 6 months ago. Improve this question
SQL – Select with group by, Get data from the register with the max(date)
I have two tables in the database: Product and ProductVersion , each product can have n ProductVersions. ProductVersion has this fields ( Id, name, origin, date, provider ) I want a query where I get …
operator ‘||’ cannot be applied to operands of type ‘string’ and ‘string’ ( how i can fix this )
This Is Windows form im newbe and i have not ton of skill but i understand i have 5 table layer = layerID int , layerName string ( layerID = PK ) Gor = LayerID int , GroID int , GroNnumber string ( GroID = PK and LayerID = FK ) Gru = GruID int , GroID int , GruNumber
How can I update my database with a loop by checking whether a column name corresponds with a button name?
So I’m making a seat reservation system for a school project and I’m stuck. I’ll explain exactly what I’m trying to do. I created this form: Seat Reservation Layout As you can see, I created a seat layout. All the seats are buttons. I also created a local SQL database with SeatID (which matches the names of the buttons exactly)
C# Get correct filpath string for SQL update Statement
I have created a small WinForms Application (.Net 4.8, SQL Server 18). Now I want to update a picture in my database. For that I have created this method: public void UpdateBild(string picturepath, …
SQLite C# System.Data.SQLite.SQLiteException
I want to insert data into a database via sqlite but each time I got the error below: Connection Established Successfully… code = Error (1), message = System.Data.SQLite.SQLiteException (0x800007BF): SQL logic error near “hpi_caseid”: syntax error at System.Data.SQLite.SQLite3.Prepare(SQLiteConnection cnn, String strSql, SQLiteStatement previous, UInt32 timeoutMS, String& strRemain) at System.Data.SQLite.SQLiteCommand.BuildNextCommand() at System.Data.SQLite.SQLiteCommand.GetStatement(Int32 index) at System.Data.SQLite.SQLiteDataReader.NextResult() at System.Data.SQLite.SQLiteDataReader..ctor(SQLiteCommand cmd, CommandBehavior behave) at