SqlException on hidden parent property

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#120 2 comments 2 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
database

Research direction

Start at the Insert call in DoInsert and trace how inherited properties are collected into SQL parameters. Reproduce the example with MyParentClass and MyChildClass, then inspect the generated parameter names. Done means the insert no longer declares duplicate @Value parameters and the example succeeds without SqlException.

Written by the indexing model from the issue text.

Description

When using the new modifier on a property within a child class both the property from the parent and child class are added to the SQL parameters causing an exception to be thrown as parameter names must be unique.

For example:

    public class MyParentClass
    {
        [Key] int Id { get; set; }
        public int Value { get; set; }
    }

    [Table("MyChildTable")]
    public class MyChildClass : MyParentClass
    {
        public new string Value { get; set; }
    }

    public class DapperStuff
    {
        private readonly IDbConnection db;
        public DapperStuff(IDbConnection db)
        {
            this.db = db;
        }
        public void DoInsert(MyChildClass insert)
        {
            this.db.Insert<MyChildClass>(insert); 
            // SqlException: The variable name '@Value' has already been declared. Variable names must be unique within a query batch or stored procedure.
        }
    }
Dominant language
C#
Stars
293
Forks
109
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