2025-12-22
560 reads
Primary Key (PK)
2025-12-15
1,364 reads
2024-01-17
469 reads
2024-01-10
528 reads
2023-11-27
6,097 reads
Questions about Primary and Foreign Keys You Were Too Shy to Ask
It is strange that one can ask simple questions about extended events or Hekaton at professional events and conferences without feeling embarrassed, yet nobody likes to ask vital questions about SQL Server primary keys and foreign keys. Fear not, here are 13 questions you were too shy to ask, answered.
2014-10-14
9,933 reads
Why Primary Keys can be important on large tables
I inherited a database that was getting large and not performing well. After adding primary keys life got better.
2014-06-30
14,715 reads
Primary Key Primer for SQL Server
Every database developer uses keys, but without always understanding all the ramifications. They come with few hard and fast rules, but if you get them right from the start with a database design, the whole process of database development is simpler, and the result is likely to perform better. We asked Phil for advice, little knowing that the explanation might take a while.
2013-12-19
5,005 reads
Primary Keys which are not Clustered Indexes in a database
Recently I was asked to find all the Primary keys that are not clustered Indexes in the database. I constructed the below script which will help us to locate the primary keys in the database which are not clustered index.
2013-09-18 (first published: 2013-09-04)
1,926 reads
2013-01-29
2,618 reads
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Fun with JSON II
Comments posted to this topic are about the item Fun with JSON II
Changing Data Types
Comments posted to this topic are about the item Changing Data Types
Question of the Day
Fun with JSON II
I have some data in a table:
CREATE TABLE #test_data
(
id INT PRIMARY KEY,
name VARCHAR(100),
birth_date DATE
);
-- Step 2: Insert rows
INSERT INTO #test_data
VALUES
(1, 'Olivia', '2025-01-05'),
(2, 'Emma', '2025-03-02'),
(3, 'Liam', '2025-11-15'),
(4, 'Noah', '2025-12-22');
If I run this query, how many rows are returned?
SELECT t1.[key] AS row,
t2.*
FROM OPENJSON(
(
SELECT t.* FROM #test_data AS t FOR JSON PATH
)
) t1
CROSS APPLY OPENJSON(t1.value) t2; See possible answers