I have the following table definition
[Table("MyTable")]
public class MyTable: BaseEntity
{
[Required]
public string A{ get; set; }
[Required]
[Column(TypeName = "json")]
public string B{ get; set; }
}
Column B looks like this:
{"Data": [{"Id":"b8a3cbbc-a4d6-4697-8a0b-cb1d15be179d"}]} (aside from Id there are other properties but for brevity I removed them)
In Entity Framework I want to match all MyTable's where the Id in B is a certain value and A has a certain value. I have tried a lot of things and get numerous errors. How can I add to the following code to achieve what I want?
var results =
_repository.Get<MyTable>(_ => _.A == "Something" && _.B = ???);
You can use "EF.Functions.JsonContains" function, but the B column needs to be "jsonb" type instead "json".
[Required]
[Column(TypeName = "jsonb")]
public string B { get; set; }
Example
var search = "[{\"Id\": \"b8a3cbbc-a4d6-4697-8a0b-cb1d15be179d\"}]";
var results = _context.MyTable2.Where(_ => _.A == "Something" &&
EF.Functions.JsonContains(_.B, search));
Similar answer HERE
Also, you can type your query and use Dapper.
Example
with temp AS(
select t."Id", t."A", json_array_elements(t."B"->'Data') as B1 from "MyTable" t
)
select * from temp t
where
t."A"='Something' and
t.b1->>'Id'='b9a3cbbc-a4d6-4697-8a0b-cb1d15be179a'
Related
I have three tables, Organization, Department, and OrganizationDepartments. here is the relationship between them.
Now I would like to join these three tables and create another object for a DTO class. This DTO object has some properties and a list of other DTOs. Here is the DTO Class.
Organization DTO:
public class OrganizationDto
{
public string Id { get; set; }
public string OrganizationName { get; set; }
public string Logo { get; set; }
public bool? IsActive { get; set; }
public IList<OrganizationDepartmentDto> OrganizationDepartments { get; set; }
}
OrganizationDepartment DTO:
public class OrganizationDepartmentDto
{
public string OrganizationId { get; set; }
public string OrganizationName { get; set; }
public string DepartmentId { get; set; }
public string DepartmentName { get; set; }
}
Now I would like to write a LINQ query to get a Organization object along with all the departments related to that organization. The query is imcomplete because I don't know how can I get all the department information as list in a single query. The code is below:
var organizationInfo = (from org in _dbContext.Organizations
join orgDept in _dbContext.OrganizationDepartments on org.Id equals orgDept.OrganizationId
join dept in _dbContext.Departments on orgDept.DepartmentId equals dept.Id
where org.Id.ToUpper() == id.ToUpper()
orderby org.CreatedOn ascending
select new OrganizationDto
{
Id = org.Id,
OrganizationName = org.OrganizationName,
Logo = org.Logo,
IsActive = org.IsActive,
OrganizationDepartments = //TODO:..
}
);
Can anyone help me to get the department lists of that organization's object (see the TODO:)?
If your entities are mapped correctly, and the relationships are correctly configured.
you can use .Include("OrganizationDepartment") and .ThenInclude("Department")to ensure relations are included into the generated Query.
If you insist on using Query Syntax. e.g from org in context.Organization
you can write out the query like this.
var q = (from org in _dbContext.Organizations
where org.Id.ToUpper() == id.ToUpper()
orderby org.CreatedOn ascending
select new OrganizationDto
{
Id = org.Id,
OrganizationName = org.OrganizationName,
Logo = org.Logo,
IsActive = org.IsActive,
OrganizationDepartments = org.OrganizationDepartments.ToList()
}
Depending on your usecase. Sometimes you are not interested in actually showing the "many to many" table outside of the scope of your database.
so it might make more sense to actually flatten the Dto.
that query would look like
var q = (from org in _dbContext.Organizations
where org.Id.ToUpper() == id.ToUpper()
orderby org.CreatedOn ascending
select new OrganizationDto
{
Id = org.Id,
OrganizationName = org.OrganizationName,
Logo = org.Logo,
IsActive = org.IsActive,
Departments= org.OrganizationDepartments.Select(t => t.Departments).ToList()
}
My query with Include generates sql with Inner join instead Left. My FK is nullable, so I can't explain such behavior. With nullable FK I am expect normal Left join.
Have I missed something?
Linq query:
var projectEntity = await _context.Projects
// few more includes were omitted
.Include(p => p.Invoice)
.FirstOrDefaultAsync(c => c.ProjectId == id);
Classes:
[Table("InvoicedHistory")]
public class InvoiceHistory
{
[Key]
[Column("InvoicedHistory_ID")]
public int InvoicedHistoryId { get; set; }
// few properties omitted
[Column("Project_ID")]
public int? ProjectId { get; set; }
}
public class Project
{
public int ProjectId { get; set; }
// few properties were omitted
[ForeignKey(nameof(InvoiceHistory.ProjectId))]
public virtual InvoiceHistory Invoice { get; set; }
}
Project class also use fluent api:
modelBuilder.Entity<Project>(entity =>
{
entity.ToTable("Projects");
entity.HasKey(e => e.ProjectId)
.HasName("PK_Project_Project_ID_Project");
// few statements were omitted
});
Sql which was generated: (Was hard to clean up this query. It contains several joins to include data for properties I have omitted)
SELECT [t].[Project_ID], [t].[Project_Client], [t].[Project_IrsDate], [t].[Project_Name], [t].[Client_ID], [t].[Client_Name], [t].[InvoicedHistory_ID], [t].[DateSubmitted], [t].[Project_ID0], [t0].[Debitor_ID], [t0].[Project_ID], [t0].[Debitor_ID0], [t0].[Address_Number], [t0].[Alias], [t0].[Alpha_Name], [t0].[Co], [t0].[Country_ID], [t0].[Currency_ID], [t0].[Havi_YesOrNo]
FROM (
SELECT TOP(1) [p].[Project_ID], [p].[Project_Client], [p].[Project_IrsDate], [p].[Project_Name], [c].[Client_ID], [c].[Client_Name], [i].[InvoicedHistory_ID], [i].[DateSubmitted], [i].[Project_ID] AS [Project_ID0]
FROM [Projects] AS [p]
INNER JOIN [Clients] AS [c] ON [p].[Project_Client] = [c].[Client_ID]
INNER **<<<<<<<<(expect LEFT)** JOIN [InvoicedHistory] AS [i] ON [p].[Project_ID] = [i].[InvoicedHistory_ID]
WHERE [p].[Project_ID] = 19922
) AS [t]
LEFT JOIN (
SELECT [p0].[Debitor_ID], [p0].[Project_ID], [d].[Debitor_ID] AS [Debitor_ID0], [d].[Address_Number], [d].[Alias], [d].[Alpha_Name], [d].[Co], [d].[Country_ID], [d].[Currency_ID], [d].[Havi_YesOrNo]
FROM [ProjectDebitors] AS [p0]
INNER JOIN [Debitors] AS [d] ON [p0].[Debitor_ID] = [d].[Debitor_ID]
) AS [t0] ON [t].[Project_ID] = [t0].[Project_ID]
ORDER BY [t].[Project_ID], [t].[Client_ID], [t].[InvoicedHistory_ID], [t0].[Debitor_ID], [t0].[Project_ID], [t0].[Debitor_ID0]
Look at this line -
INNER <<<<<<<<(expect LEFT)<<<<<< JOIN [InvoicedHistory] AS [i] ON [p].[Project_ID] = [i].[InvoicedHistory_ID]
Inner join makes my query return nothing, because I have no invoice info. If I manually replace it with Left join, sql query will return me all necessary data.
I think you can use Fluent API to get your desired result:
modelBuilder.Entity<Project>()
.HasOne(p => p.Invoice)
.WithOne()
.HasForeignKey(ih => ih.ProjectId);
This should change it to a left join because we didn't specify .IsRequired()
As mentioned in the following SO Answer - Equivalent for .HasOptional in Entity Framework Core 1 (EF7)
You will not find an equivalent method in EF 7. By convention, a property whose CLR type can contain null will be configured as optional. So what decide if the relationship is optional or not is if the FK property is nullable or not respectively.
and
In case of your FK property is value type like int, you should declare it as nullable (int?).
Now most likely your problem with annotations is that the following is not doing what you think it is:
[ForeignKey(nameof(InvoiceHistory.ProjectId))]
//Does not resolve to:
[ForeignKey("InvoiceHistory.ProjectId")]
//Does resolve to:
[ForeignKey("ProjectId")]
Now even if that is what you are looking for, the order of operations for the ForeignKey detection is to check the parent type then the property type.
public class InvoiceHistory
{
public int? ProjectId { get; set; }
}
public class Project
{
public int ProjectId { get; set; }
// this is pointing to Project.ProjectId
// and Project.ProjectId is not nullable
// so the join becomes an inner join
// and really only works because they both have the same name
[ForeignKey(nameof(InvoiceHistory.ProjectId))]
public virtual InvoiceHistory Invoice { get; set; }
}
If you wanted this to work as pointing to the Property Type, you need to rename the InvoiceHistory name:
public class InvoiceHistory
{
public int? ProjectFk { get; set; }
}
public class Project
{
public int ProjectId { get; set; }
// this is pointing to InvoiceHistory.ProjectFk
// because there is no Project.ProjectFk
[ForeignKey(nameof(InvoiceHistory.ProjectFk))]
public virtual InvoiceHistory Invoice { get; set; }
}
EntityFramework Data Annotations
If you wanted to see it create bad SQL you could do this:
public class InvoiceHistory
{
public int? ProjectId { get; set; }
}
public class Project
{
public int ProjectFk { get; set; }
[ForeignKey("ProjectFk")]
public virtual InvoiceHistory Invoice { get; set; }
}
EF will then create:
INNER JOIN [InvoicedHistory] AS [i] ON [p].[Project_ID] = [i].[ProjectFk]
And will cause a SqlException with the message something like Invalid column name.
I've seen an answer to a similar problem (Entity framework and Exists clause), but not using lambda and I would like to understand what is wrong,
whether it is my mapping or if is the way to use. I'm using Entity Framework 5.
Here is my mapping:
public class Attribute : EntityWithGuid
{
... Other mappings ....
[InverseProperty("Attribute")]
public virtual ICollection<CategoryAttribute> CategoryAttributes { get; set; }
}
public class Category : EntityWithGuid
{
... Other mappings ....
[InverseProperty("Category")]
public virtual ICollection<CategoryAttribute> CategoryAttributes { get; set; }
}
public class CategoryAttribute : EntityWithGuid
{
... Other mappings ....
[ForeignKey("Category_Id")]
public virtual Category Category { get; set; }
public string Category_Id { get; set; }
[ForeignKey("Attribute_Id")]
public virtual Attribute Attribute { get; set; }
public string Attribute_Id { get; set; }
}
If I run the command below, it works fine and the result SQL is
var query = Attribute.Where(x => !x.CategoryAttributes.Any());
SELECT
Extent1.Id,
Extent1.Name,
Extent1.Type,
Extent1.Active
FROM
Attribute AS Extent1
WHERE
NOT EXISTS( SELECT
1 AS C1
FROM
CategoryAttribute AS Extent2
WHERE
Extent1.Id = Extent2.Attribute_Id)
But if I put one more clause appears a Project2 alias for Attribute instead Extent1 and gives error because inside the exists clause within the remains Extent1.Id
var query = Attribute.Where(x => !x.CategoryAttributes.Any(y=>y.Category_Id == idcategory));
SELECT
Project2.Id,
Project2.Name,
Project2.Type,
Project2.Active
FROM
Attribute AS Project2
WHERE
NOT EXISTS( SELECT
1 AS C1
FROM
CategoryAttribute AS Extent2
WHERE
(Extent1.Id = Extent2.Attribute_Id)
AND (Extent2.Category_Id = #p__linq__0))
The exception is
Unknown column 'Extent1.Id' in 'where clause'
Found the problem.
After performing a simple query and receive an error similar thought something was wrong. Below the query, SQL and the undesirable alias Project
User.Where(x => x.Name.Contains(partialName))
SELECT
Project1.Id,
Project1.Name
FROM
User AS Project1
WHERE
(LOCATE('Marcelo', Extent1.Name)) > 0
ORDER BY Project1.Name ASC
Recently I upgraded MySql and with it came the new Net connector, version 6.7.4. I went back to the previous Net connector version (6.5.6) and everything is working again.
Got a very difficult EntityFramework Code First question. I'll keep this as simple as possible.
Imagine we have n number of classes, lets start with 2 for now
public class Person
{
public string Name { get; set; }
}
public class Address
{
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
}
Now then, what I want to do is be able to search the domain model with a single string, i.e. something like DbContext.Search( "Foo" ). The call would search both the person and address tables for a string match and would return a list populated with both Person and Address entities.
Have to say I am not entirely clear how to go about it but I am considering using DataAnnotations to do something like this
public class Person
{
**[Searchable]**
public string Name { get; set; }
}
public class Address
{
**[Searchable]**
public string AddressLine1 { get; set; }
**[Searchable]**
public string AddressLine2 { get; set; }
}
Am I on the right track?
Should I use the Fluent API instead?
Reflection?
Any and all thoughts massively appreciated.
the Find method searches only in the Primary Key column. If we don't make any column explicitly primary key column then find method will throw error. Generally EF convention takes propertyName+id as the primary key in the class. But if you want to search with Name then Make add [Key] to the property. it will become primary key and u will be able to find properties.
dbContext.Addresses.find("Foo");
Create a new object type onto which you'll project 2 types of search results:
public class Result
{
public string MainField { get; set; }
// you may have other properties in here.
}
Then find entities of each type that match your criteria, projecting them onto this type:
var personResults = DbContext.Persons
.Where(p => p.Name == "Foo")
.Select(p => new Result{MainField = p.Name});
// don't forget to map to any other properties you have in Result as well
var addressResults = DbContext.Adresses
.Where(a =>
a.AddressLine1 == "Foo" ||
a.AddressLine2 == "Foo"
).
.Select(a => new Result{MainField = a.AddressLine1 + ", " + a.AddressLine2 });
// again, don't forget to map to any other properties in Result
Then merge the lists:
var allResults = personResults.Union(addressResults).ToList();
...at which point you can sort the list however you like.
"Result" and "MainField", are rather generic; just using them because I am not thoroughly aware of your domain model.
I have the following enum and POCO class
public enum Gender
{
Male,
Female,
Unknown
}
public class Person
{
public int PersonId { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
public Gender? Gender { get; set; }
}
I would like to perform a "get all people" query in my repository such that it would look something like this:
return from p in _db.People
select new Model.Person
{
PersonId = p.PersonId,
LastName = p.LastName,
FirstName = p.FirstName,
Gender = p.Gender,
};
Unfortunately I get an error "Cannot implicitly convert type 'string' to 'Model.Gender'"
I would like to convert the string which is being queried from the entity framework to my Gender enum and assign it to my POCO class.
Enums are not supported in Entity Framework. There is a workaround by Alex James, but it's quite involved.
Instead, i prefer to do this:
public enum Gender : byte
{
Male = 1,
Female,
Unknown
}
public class Person
{
public int PersonId { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
public byte Gender { get; set; } // this is the EF model property
public Gender GenderType // this is an additional custom property
{
get { return (Gender) Gender; }
set { Gender = (byte)value; }
}
}
It's basically a hook/wrapper for the actual value. In your database, store Gender as a tinyint (which maps to byte on the conceptual side).
Then you can use a byte enum to map to and from the model property:
return from p in _db.People
select new Model.Person
{
PersonId = p.PersonId,
LastName = p.LastName,
FirstName = p.FirstName,
Gender = p.Gender, // sets byte
};
But then if you access that ViewModel, because your setting the byte field for Gender, you will also have access to the enum property GenderType.
Does that solve your problem?
The Entity Framework that I am familiar with does not provide support for enums. EF uses your query expression to create an SQL statement that it then sends to the server, if it cannot create the SQL equivalent of some operation it will throw a NotSupportedException for that operation. If you are expecting to return a small set of data you can separate from the Entity Framework by creating an object in memory using the ToArray method.
var myEntities = (from entity in _db.Entities
where /* condition */
select entity)
.ToArray();
This will create a sequence of entities in memory. Any further query statements will then be in the realm of LINQ to Objects which allows parsing of strings into enums:
return from myEntity in myEntities
select new MyDataContract
{
ID = myEntity.ID,
Gender g = (Gender)Enum.Parse(typeof(Gender), myEntity.Gender, true)
};
Or you could even break it out into a foreach loop:
List<MyDataContract> myDataContracts = new List<MyDataContract>();
foreach (var myEntity in myEntities)
{
var dataContract = new MyDataContract { ID = myEntity.ID };
if (Enum.IsDefined(typeof(Gender), myEntity.Gender))
dataContract.Gender = (Gender)Enum.Parse(typeof(Gender), myEntity.Gender, true);
myDataContracts.Add(dataContract);
}
return myDataContracts.AsEnumerable();
if (Enum.IsDefined(typeof(Gender), genderstring))
Gender g = (Gender) Enum.Parse(typeof(Gender), genderstring, true);
else
//Deal with invalid string.
try
Gender = p.Gender != null ? (Gender)Enum.Parse(typeof(Gender), p.Gender) : (Gender?)null;
To parse the string as one of the enums
here's a workaround but it means changing your nice and clean POCO
http://blogs.msdn.com/b/alexj/archive/2009/06/05/tip-23-how-to-fake-enums-in-ef-4.aspx