<div>
Ok, but how do I write this when I create the table? Do I have to make something special in the create table -statement?
</div>


Ok, but how do I write this when I create the table? Do I have to make something special in the create table -statement?

<div>
That's a FK that's reference a PK in the same table so you can use the same statement as you're using for relationship creation. If you have doubts please read this <a href="https://docs.microsoft.com/en-us/sql/relational-databases/tables/create-foreign-key-relationships" rel="ugc">MSDN article</a> that explains about creating FKs.
</div>


That's a FK that's reference a PK in the same table so you can use the same statement as you're using for relationship creation. If you have doubts please read this MSDN article [https://docs.microsoft.com/en-us/sql/relational-databases/tables/create-foreign-key-relationships] that explains about creating FKs.

<div>
<div class="content wysiwyg-content">
Hi!<br />
<br />
I am studying and trying to rebuild an example from this page: <a href="https://www.toptal.com/sql/interview-questions" rel="ugc">https://www.toptal.com/sql/interview-questions</a>&nbsp;I Understand the reference between the primary key in table Customers and Id in table Invoices. But I don´t understand what the relation between the primary key Id and the field RefferedBy means? <a href="https://filedb.experts-exchange.com/incoming/2017/09_w37/1193525/table_internal_reference.PNG" target="_blank" title="internal_table_reference (9 KB)"><img alt="internal_table_reference" class="file-block lazyload" style="max-width: 460px;" data-src="https://filedb.experts-exchange.com/incoming/2017/09_w37/1193525/table_internal_reference.PNG" /></a><br />
I want to know so I can create examples to make sure that I really understand the sql-code in the example from the page.<br />
<br />
Regards
</div>
</div>


table_internal_reference.PNG

Hi!

I am studying and trying to rebuild an example from this page: https://www.toptal.com/sql/interview-questions I Understand the reference between the primary key in table Customers and Id in table Invoices. But I don´t understand what the relation between the primary key Id and the field RefferedBy means? 

I want to know so I can create examples to make sure that I really understand the sql-code in the example from the page.

Regards

What does this table internal reference mean?

Databases are organized collections of data, most commonly accessed through management systems including schemas, tables, queries and processes that allow users to enter and manipulate the information or utilize it in other fashions, such as with web applications or for reporting purposes.

Databases

Microsoft SQL Server is a suite of relational database management system (RDBMS) products providing multi-user database access functionality.SQL Server is available in multiple versions, typically identified by release year, and versions are subdivided into editions to distinguish between product functionality. Component services include integration (SSIS), reporting (SSRS), analysis (SSAS), data quality, master data, T-SQL and performance tuning.