Dapper Tutorial - Knowledge Base (KB)
1114 results for: in tag: c#
Where to put sql when using dapper?
I'm using dapper for a mvc3 project at work, and I like it. However, how are you supposed to layer the application when using dapper? Currently I just have all my sql stuffed directly in the controller (...slap...) but I was thinking of making a class wit...
asked by Christian Wattengård
Can't get multi-mapping to work in Dapper
Playing around with Dapper, I'm quite pleased with the results so far - intriguing!...But now, my next scenario would be to read data from two tables - a ...Student... and an ...Address... table....Student... table has a primary key of ...StudentID (INT I...
asked by marc_s
How to name columns for multi mapping support in Dapper?
var sql = @"SELECT a.id AS `Id`, a.thing AS `Name`, b.id AS `CategoryId`, b.something AS `CategoryName` FROM .."; var products = connection.Query<Product, Category, Product>(sql, (product, category) => { product.Catego...
asked by loraderon
Using Dapper to populate Enum properties
In using Dapper's Query() function, I am trying to fill in a class that has a property which is an enumerated value. In my database, this column is stored as a byte. However, in the class, they are an enum. In the old ADO.NET approach, I'd convert duri...
asked by Slaggg
How do I select an aggregate object efficiently using Dapper?
Lets say that I have a series of objects that form an aggregate....public class C{ public string Details {get;set;} } public class B{ public string Details {get;set;} public List<C> Items {get;set;} } public class A{ public long ID {get;set;} p...
asked by Peter
Dapper and anonymous Types
Is it possible to use anonymous types with Dapper?...I can see how you can use dynamic i.e. ...connection.Query<dynamic>(blah, blah, blah) ...is it then possible to do a ....Select(p=> new { A, B ,C }) ...or some variation of that afterwards?...Edit...I...
asked by Peter
Is there a way to access the columns in a Dapper FastExpando via string or index?
I am pulling in a ...Dapper FastExpando... object and want to be able to reference the column names dynamically at run time rather than at design/compile time. So I want to be able to do the following:...var testdata = conn.Query("select * from Ride Wher...
asked by Jay Stevens
Using Dapper with Oracle
We use Oracle as our database provider and have looked into replacing some of our data access layer (hard to maintain, harder to merge XSD's) with a saner repository based pattern using Dapper at the bottom layer. However, we have hit a number of issues w...
asked by Wolfwyrd
Clarification of Dapper Example Code
I'm trying to grok Dapper and seem to be missing something very fundamental, can someone explain the following code taken from the Dapper home page on Google code and explain why there is no From clause, and the second param to the Query method (dynamic) ...
asked by Stephen Patten
Can AnsiStrings be used by default with Dapper?
I'm using Dapper against a database where strings are stored primarily in ...VarChar... columns. By default Dapper uses ...NVarChar... parameters when generating queries and while I can wrap each and every string parameter I use with ...DbString... it'd b...
asked by John Foster
How to insert an IEnumerable<T> collection with dapper-dot-net
Yep, there are ...questions here... and ...here... about how to insert records with dapper-dot-net. However, the answers, while informative, didn't seem to point me in the right direction. Here is the situation: moving data from SqlServer to MySql. Readin...
asked by IAbstract
Read/Write distribution over MySQL Master/Slaves using Dapper
Would dapper have any problems with using two IDbConnection objects for distributing Writes and Reads between MySQL Master/Slaves?
asked by Kynth
Dapper parameterised queries with LINQ autogenerated types
I'm using a combination of LINQ and Dapper in my work. I'm replacing my LINQ code with Dapper in places for performance reasons. I have a lot of LINQ data objects created by dragging and dropping into the Visual Studio database diagram from SQL Server..
asked by Giles Roberts
Dapper multiselect: Nested class primary key doesn't map unless using "AS"
I have two classes:...class Foo{ public int FooId { get; set; } ... public Bar Bar { get; set } } class Bar{ public int BarId { get; set; } public int FooId { get; set } ... } ...when i then run the query like this:...sqlConnectio...
asked by Joakim
Unexpected behaviour with a multi-mapping query using Dapper.net
I've only just started looking at Dapper.net and have just been experimenting with some different queries, one of which is producing weird results that i wouldn't expect....I have 2 tables - ...Photos... & ...PhotoCategories..., of which are related on ..
asked by marcusstarnes
Dapper - like operator using DynamicParameters
This works:...var list = conn.Query<int>( "select Id from Person where Id in @ids", new { ids = new int[] { 1, 2, 3 } } ); ...This throws "No mapping exists from object type System.Int32[] to a known managed provider native type.":...DynamicParameter...
asked by Trev
How to map multiple records from a single SP with Dapper-dot-net
I'd like to use Dapper in a situation where the execution of a single stored procedure will return 50 multiple separate selects, none of the individual result sets will be very wide, maybe 20 or 30 columns at most. The code below is from the Dapper Tests ...
asked by Stephen Patten
How to periodically flush dapper.net cache when used with SQL Server
Can someone please explain what this means (from the Dapper.net website)...Limitations and caveats...Dapper caches information about every query it runs, this allow it to materialize objects quickly and process parameters quickly. The current implementati...
asked by Gullu
Recommended asp.net MVC model design approach
I'm trying to decide the best approach for a new project I'm about to start on, when it comes to my model design (and I'm using Dapper.net)....I like the idea of having my models with objects rather than Foreign Key properties, i.e....public Post LastPost...
asked by marcusstarnes
Dapper - Sql to Object implicit cast from string to int
I'm using dapper and am having issues with casting a string value from the db to an int. Has anyone overriden the TypeMap to allow for this?...Any suggestions would be great.
asked by Arnej65
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