Want to create index by EmployeeCardNumber (text) in descending order.
So the sql script should be like:
ALTER TABLE dbo.Employees ADD CONSTRAINT
IX_Employees_EmplyeeCardNumber UNIQUE CLUSTERED
(
EmployeeCardNumber DESC
)
In IndexAttribute, there is an Order property, which is an integer???
Here is my fluent api:
var indexAttr = new IndexAttribute("IX_Employees_EmplyeeCardNumber")
{
IsClustered = true,
IsUnique = true,
Order = 1 // probably should be removed since we are using a composite key.
};
Property(c => c.EmployeeCardNumber)
.HasColumnAnnotation("Index", new IndexAnnotation(indexAttr))
.HasMaxLength(8)
.IsRequired();
So the question is, how to define "DESC" in this code first approach?
Related
I need to use Fluent API (no DataAnnotation) and should create complex Index (3 fields). I try to do it:
this.HasIndex(p => p.LoadId).HasName("IX_UniqueLoad").IsUnique();
this.HasIndex(p => p.LocationId).HasName("IX_UniqueLoad").IsUnique();
this.HasIndex(p => p.StopAction).HasName("IX_UniqueLoad").IsUnique();
but it says:
The index with name 'IX_UniqueLoad' on table 'dbo.Stop' has the same
column order of '-1' specified for columns 'LoadId' and 'LocationId'.
Make sure a different order value is used for the IndexAttribute on
each column of a multi-column index.
How to do it?
I found solution:
this.HasIndex(p => new { p.LoadId, p.LocationId, p.StopAction }).IsUnique();
it will generates:
CreateIndex("dbo.Stop", new[] { "LoadId", "LocationId", "StopAction" }, unique: true);
Using the Entity Framework 6.1 code first model, what is the best way to go about changing the clustered index on a table from the default ID to another set of columns. Azure doesn't allow a table without a clustered index.
public partial class UserProfile
{
public override Guid ID { get; set; }
[Index( "CI_UserProfiles_UserID", IsClustered = true)]
public Guid UserID { get; set; }
[Required]
public Guid FieldID { get; set; }
[Required]
[StringLength(400)]
public string Value { get; set; }
}
On the table UserProfiles, ID is already the primary key and clustered index. Adding
[Index( "CI_UserProfiles_UserID", IsClustered = true)]
to UserID creates this migration:
CreateIndex("dbo.UserProfiles", "UserID", clustered: true, name: "IX_UserProfiles_UserID");
Executing the migration generates the following error:
Cannot create more than one clustered index on table 'dbo.UserProfiles'. Drop the existing clustered index
'PK_dbo.UserProfiles' before creating another.
To solve your problem, after you generate your migration file, you must modify the generated code by disabling clustered index for your primary key by assigning false as a value of clustered parameter of PrimaryKey.
After your modifications you must have something like this into your migration file:
CreateTable(
"dbo.UserProfiles",
c => new
{
Id = c.Guid(nullable: false),
UserID = c.Guid(nullable: false),
FieldID = c.Guid(nullable: false),
Value = c.String(nullable: false, maxLength: 400),
})
.PrimaryKey(t => t.Id, clustered: false)
.Index(t => t.UserID, clustered: true, name: "CI_UserProfiles_UserID");
This is not done in OnModelCreating method by using Fluent API like Manish Kumar said, but in migration file. The file that is created when you use Add-Migration command.
Existing Database
As you say in comments, your database already exist. After executing Add-Migration command, you will have this line on your DbMigration file in your Up() method:
public override void Up()
{
CreateIndex("dbo.UserProfiles", "UserID", clustered: true, name: "CI_UserProfiles_UserID");
}
You must modify the Up() method to have this code:
public override void Up()
{
this.Sql("ALTER TABLE dbo.UserProfiles DROP CONSTRAINT \"PK_dbo.UserProfiles\"");
this.Sql("ALTER TABLE dbo.UserProfiles ADD CONSTRAINT \"PK_dbo.UserProfiles\" PRIMARY KEY NONCLUSTERED (Id);");
this.CreateIndex("dbo.UserProfiles", "UserID", clustered: true, name: "CI_UserProfiles_UserID");
}
In the code above I assumed that the created clustered index is named PK_dbo.UserProfiles in your database. If not then put at this place the correct name.
This is truly an area where EntityFramwork (Core) had to advance and it still is hard.
So, I could not use IsClustered(false) for my GUID / string Primary keys, for the simple reason, the project having DbContexts was DB - agnostic. So you needed to Add EntityFrameworkCore.SqlServer and IsClustered is available then, and only.
So, my solution was simple. Add no nuget package but this attribute.
This ONLY works on EF Core.
I have tested this on SQL. Though, not sure if the other providers would allow this string not having any meaning. (e.g. SQLite does not know clustered indexes)
p.HasKey(k => k.Id).HasAnnotation("SqlServer:Clustered", false);
You need to remove the existing clustered index from your current PK 'ID' which is created by default for any "KEY" property in code first. It can be done using fluent API:
.Primarykey(x=>x.ID,clustered:false)
Once existing clustered index is removed from ID, your migration to add the clustered index on UserID should run smoothly.
After the migration file is created, modify the generated code, disabling the clustered index for the primary key by setting the clustered property to false.
Being that Azure does not allow a table without a clustered index, and there is no utility in SQL Server to 'change' a clustered index on a table, it is necessary create a new table with the clustered index and migrate the existing data to it. The code below renames the original table, migrates the data to the new table that was created with the new clustered index and drops the original table.
RenameTable("dbo.UserProfiles", "UserProfiles_PreMigrate");
CreateTable(
"dbo.UserProfiles",
c => new
{
Id = c.Guid(nullable: false),
UserID = c.Guid(nullable: false),
FieldID = c.Guid(nullable: false),
Value = c.String(nullable: false, maxLength: 400),
})
.PrimaryKey(t => t.Id, clustered: false)
.Index(t => t.UserID, clustered: true, name: "CI_UserProfiles_UserID");
Sql(#"
INSERT [dbo].[UserProfiles]
(ID,
UserID,
FieldID,
Value)
SELECT
ID,
UserID,
FieldID,
Value
FROM dbo.UserProfiles_PreMigrate
");
DropTable("UserProfiles_PreMigrate");
Any existing table constraints will be lost in this operation, so it will be necessary to recreate and indexes,foreign keys, etc on the table.
I'm use Entityframework Code First, and an EntityTypeConfiguration using fluent API.
how can create Unique Constraint with multi column.
for example i have a table with below field
Id
CompanyId
Code
Name
i want set Code column to unique , per CompanyId
In your EntityTypeConfiguration you can do something like this:
Property(m => m.CompanyId)
.HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_YourUniqueIndexName", 1) { IsUnique = true }));
Property(m => m.Code)
.HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("IX_YourUniqueIndexName", 2) { IsUnique = true }));
This will create a unique index on those 2 columns.
Make sure you use the same name for the unique index. Both need to be name "IX_YourUniqueIndex". If one is called "IX_Index1" and the other "IX_Index2" then it will create a unique index on each, which is not what you want
I'm using EF5 code first and now I need to update my database so I enabled database migrations and added a migration but the generated code was not what I needed. This is the code:
public override void Up()
{
CreateTable(
"dbo.HistoricalWeightEntities",
c => new
{
PatientMedicalDataId = c.Guid(nullable: false),
Id = c.Guid(nullable: false),
Weight = c.Single(nullable: false),
Date = c.DateTime(nullable: false),
})
.PrimaryKey(t => new { t.PatientMedicalDataId, t.Id })
.ForeignKey("dbo.PatientMedicalDataEntities", t => t.PatientMedicalDataId, cascadeDelete: true)
.Index(t => t.PatientMedicalDataId);
AddColumn("dbo.PatientDataEntities", "PatientDataFilePath", c => c.String());
//Here I need to move data from the old Weight column to the Weight column on the newly
//created table and create the id (Guid) and the foreing key before the old
//column is dropped
DropColumn("dbo.PatientMedicalDataEntities", "Weight");
}
What I need to do is to add some sql script that move data from the 'Weight' column in the dbo.PatientMedicalDataEntities to the Weight column in the newly created table dbo.HistoricalWeightEntities and also insert the Id value (key) which is a Guid and the corresponding foreign key before the column is dropped.
Can somebody show me how to do this is sql?
Thank you in advance
It should be something like that (donnow what you wanna do with the Date column)
Sql("INSERT INTO HistoricalWeightEntities(Id, Weight, PatientMedicalDataId) "+
"SELECT newid(), Weight, <theForeignKeyColumn> from PatientMedicalDataEntities");
Hope someone can help me out here as I'm a little stuck.
I'm building a service in front of a hiscore database for a game.
The database have the following two tables:
CREATE TABLE [dbo].[PB_HiscoreEntry] (
[Id] UNIQUEIDENTIFIER NOT NULL,
[PlayerId] UNIQUEIDENTIFIER NOT NULL,
[Score] INT NOT NULL,
[DateCreated] DATETIME NOT NULL
);
CREATE TABLE [dbo].[PB_Player] (
[Id] UNIQUEIDENTIFIER NOT NULL,
[UniquePlayerId] NCHAR (32) NOT NULL,
[Name] NVARCHAR (50) NOT NULL,
[DateCreated] DATETIME NOT NULL
);
The idea is of course to only have each player once in the database and let them have multiple hiscore entries. This table PB_HiscoreEntry will have a lot of scores, but by doing a simple OrderBy descending, I can create a real hiscore list where the one with highest score is at the top and the lowest at the bottom.
My problem here is that my database don't have any idea of the actual Rank of the score compared to the others. This is something I should do as I do the OrderBy query described above.
Here is some code to help illutrate what I want to archive:
var q = (
from he in entities.PB_HiscoreEntry
orderby he.Score descending
select new HiscoreItem()
{
UserId = he.PB_Player.UniquePlayerId,
Username = he.PB_Player.Name,
Score = he.Score,
//Put in the rank, relative to the other entires here
Rank = 1
});
HiscoreItem, is just my own DTO i need to send over the wire.
So anybody have an idea of how I can do this or am I on a totally wrong path here?
You're on the right track, you just need to use the Queryable.Select overload that takes an extra index. Take a look at this:
var entries =
from entry in entities.PB_HiscoreEntry
orderby entry.Score descending
select entry;
// Note the (entry, index) lambda here.
var hiscores = entries.Select((entry, index) => new HiscoreItem()
{
UserId = entry.PB_Player.UniquePlayerId,
Username = entry.PB_Player.Name,
Score = entry.Score,
Rank = index + 1
});
I'm not 100% sure if Entity Framework knows how to work with the
Select<TSource, TResult>(this IQueryable<TSource>, Expression<Func<TSource, int, TResult>>) overload. If that's the case, just use the equivalent method of the static Enumerable class:
// Note the .AsEnumerable() here.
var hiscores = entries.AsEnumerable()
.Select((entry, index) => new HiscoreItem()
{
UserId = entry.PB_Player.UniquePlayerId,
Username = entry.PB_Player.Name,
Score = entry.Score,
Rank = index + 1
});
I hope this helps.