README.md

DapperUtils

Bits of code to make working with dapper more enjoyable.

DapperProviderBase

Dapper provider base is a base class that contains a few useful methods when creating Dapper-based providers. Dapper allows you to execute queries against sql server and maps the results to .NET objects.

Examples below:

1) Retrieval of a entity using a stored procedure

public class DomainSpecifficReadProvider : DapperProviderBase 
{
    ...

    public async Task<DomainEntity> GetDomainEntityAsync(string domainEntityId)
    {
        string command = "EXEC GET_DOMAIN_ENTITY_BY_ID @DOMAIN_ENTITY_ID";
        var parameters = new DynamicParameters();
        parameters.Add("DOMAIN_ENTITY_ID", domainEntityId);

        var cd = new CommandDefinition(command, parameters);
        IEnumerable<DomainEntityReadModel> domainEntities = await ConnectAsync(c => c.QueryAsync<DomainEntityReadModel>(cd));
        
        ...
    }
    ...
}

The relevant properties of this entity must be decorated with the ColumnAttribute like in the example below:

    using System.Data.Linq.Mapping;

    class DomainEntityReadModel
    {
        [Column(Name = "DOMAIN_ENTITY_ID")]
        public int DomainEntityId { get; set; }

        [Column(Name = "DOMAIN_ENTITY_NAME")]
        public string DomainEntityName { get; set; }

        [Column(Name = "DOMAIN_ENTITY_DESCRIPTION")]
        public string DomainEntityDescription { get; set; }

        [Column(Name = "DOMAIN_ENTITY_CODE")]
        public string DomainEntityCode { get; set; }
    }

Needles to say that the names you specify here must match the column names returned by your database query.

2) Passing table-valued parameters to a query

public class CustomersWriteProvider : DapperProviderBase 
{
    ...
    public async Task<int> CreateCustomerAsync(Customer customer)
    {
        DataTable phones = CreateTable(customer.Phones.Select(c => new PhoneWriteModel { PhoneTypeId = (int)c.Type, PhoneNumber = c.Number }));

        string command = "EXEC CREATE_CUSTOMER @FIRSTNAME, @LASTNAME, @EMAIL, @Phones, @CUSTOMER_ID OUTPUT";

        DynamicParameters dp = new DynamicParameters();
        dp.Add("FIRSTNAME", customer.FirstName);
        dp.Add("LASTNAME", customer.LastName);
        dp.Add("EMAIL", customer.Email);

   x    dp.Add("Phones", phones.AsTableValuedParameter("PhonesTableType"));

        dp.Add("CUSTOMER_ID", 0, DbType.Int32, ParameterDirection.Output);

        var cd = new CommandDefinition(command, dp);

        int affectedRows = await ConnectAsync(c => c.ExecuteAsync(cd));
        customer.Id = dp.Get<int>("CUSTOMER_ID");

        return customer.Id;
    }
    ...
}

As you can see on the lines marked with an x the parameters are added "AsTableValuedParameter" and here you must pass the exact name you used in sql server to define your parameter table type.

The PhoneWriteModel has to match the structure of the parameter table type you have in sql server:

    class PhoneWriteModel
    {
        [Column(Name = "PHONE_ID")]
        public int PhoneId { get; set; }

        [Column(Name = "PHONE_NUMBER")]
        public string PhoneNumber { get; set; }

        [Column(Name = "PHONE_TYPE_ID")]
        public int PhoneTypeId { get; set; }
    }

Happy coding.