Data Tips & Tricks

Sometimes in the large project when we separate it in different repositories we need to take reference of one repository in another where some the sub-module concepts. Now if we move our submodule to a different repository or renaming its repo-path then we've to also update the repository where this sub-module is getting referenced. Let's see how to update the git submodule.  Step-1: First clone the repo Step-2: Open git UI to create a new local branch from master  Step-3: Open git bash -- Now run below command to (remove submodules & add them):  -- Remove submodule git submodule deinit YOUR_FIRST_REPO git rm YOUR_FIRST_REPO git commit -m "Removed submodule YOUR_FIRST_REPO" rm -rf .git/modules/YOUR_FIRST_REPO -- Add submodule git submodule add <<..YOUR_FIRST_REPO git URL>> Step-4: All good, let's push our changes to the master

While working with Azure SQL using SQL server management studio (SSMS), most of the feature which we used to get through SSMS GUI while connecting with OnPre/IaaS SQL-Server, is not available (e.g.: get the user's role assignment, create user/role ..) Here are a few useful T-SQL queries: To create a role Create Role IF DATABASE_PRINCIPAL_ID('<<your-role-name>>') IS NULL BEGIN -- Add Role here CREATE ROLE [<<your-role-name>>]; END To create a user Create User if not exists [<<your-user-name>>] IF NOT EXISTS (SELECT [name] FROM sys.database_principals WHERE [name] = '<<your-user-name>>' ) BEGIN CREATE USER [< >] FROM EXTERNAL PROVIDER ; END Get user role & grant permission summary Role & grant permission summary: SELECT DISTINCT pr.principal_id, pr.name, pr.type_desc, pr.authentication_type_desc, pe.state_desc, pe.permiss...

Search in SQL server query is generally case insensitive (by default or based on database level collation). Suppose we have an employees table with a row having first-name column value as "My-First-Name", so if we want to do the case-sensitive search we have to explicitly use the related collate: In EF 5 (currently in Release Candidate version [RC.2.20475.6]) Collate function got introduced which helps us to use our specific collation based search.  C# with EF5 code sample: var employeeCaseSensitiveSearch = _dbContext.Employees .Where(x => EF.Functions.Collate(x.FirstName, "Latin1_General_CS_AS") == "my-first-name") .FirstOrDefault(); A related database query will be something like this: T-SQL: Case sensitive search (use specific collation e.g.: Latin1_General_CS_AS) SELECT * FROM dbo.Employees AS e WHERE e.FirstName Collate Latin1_General_CS_AS = 'my-first-name' Some of the useful CSharp function which g...

Why my update command using EFCore is not updating the underlying data in the database though in middle-tier code it's successful, not throwing any error? Let's try to get the root cause and how to solve this.  When creating the model class of related database object if the primary key name is Id then no need to explicitly mention the Key in ef-core OnModelCreating.  But if we've key name different from Id then we have to explicitly mention it in our OnModelCreating. Something like this:  entity.HasKey(c => new {c.CustId }); Assume in the database we've Customers table like this: CREATE TABLE [dbo].[Customers]( [CustId] [INT] IDENTITY(1,1) NOT NULL Primary Key, [FirstName] [VARCHAR](50) NULL ) Point to ponder: In the database table, column CustId is already defined as Primary key.  In EFCore model setup, it's up to us to configure the Key as (custId) or configure it as HasNoKey() Assume we've set our entity with Ha...

EFCore versions, we don't have GUI to manage the DB-entities & dbContext like we used to have with EF6 (or EF5/4 version). With EFCore we've the Scaffold-DbContext command which helps us to create entities & DB context from our DB-objects.  Let's see how to use Scaffold-DbContext: Assume we're connecting with SQL Server so after creating a sample project you'll have to install EFCore related libraries as mentioned below.  Install entity-framework-core for SQL Server, at this time 3.1.9 is the latest stable version   Microsoft.EntityFrameworkcore   Microsoft.EntityFrameworkCore.SqlServer  To use Scaffold-DbContext, following two NuGet packages are required Microsoft.EntityFrameworkCore.Tools  Microsoft.EntityFrameworkCore.Design Let's say we've two DB tables (e.g. dbo.Employees & dbo.Users )  Now let's see how to use Scaffold-DbContext to create c-...

Practically there are multiple instances when we want to do parallel DB call which will save us some time. Like if we want to get a few employees details as well as users detail and if both entities are independent of each other better to go with a parallel call to fetch the details.  With the growing ORM usage and enhanced & optimized framework of like EFCore, in most of the application (related to C# development), we generally prefer to use EFCore. With EFCore if we try to use the same DB context to do parallel db call we are getting an error (... different thread using the same DbContext....). Because dbContext call is not thread-safe Parallel DB call on the same dbContext:  Code snipped: which will throw an error private void DbCallWithParallelCallOnSameDbContext() { try { var employeesTask = _dbContext.Employees.ToListAsync(); var usersTask = _dbContext.Users.ToListAsync(); ...