database design - When should a primary key be meaningful?
Mar 18, 2018 · A Primary Key uniquely identifies a row. There are possibly other columns in a table with unique values, so they can also uniquely identify a row (Candidate Keys), but the Primary Key is the …
What is the difference between a primary key and a superkey in a DBMS
Jul 20, 2014 · A Primary Key is a minimal Candidate Key, which is to say all constituent columns are strictly required in order to ensure uniqueness. As a database developer/designer of 30 years …
database design - Are composite primary keys bad practice?
Oct 21, 2017 · I want to know if composite primary keys are bad practice and if not, in which scenarios is their use beneficial? My question is based on this article Note the part about composite primary keys: ...
Add auto increment to already existing primary key column PostgreSQL
Feb 23, 2021 · Add auto increment to already existing primary key column PostgreSQL Ask Question Asked 4 years, 11 months ago Modified 4 years, 11 months ago
NVARCHAR column as PRIMARY KEY or as UNIQUE column
Feb 10, 2015 · Is [ID_CODE], as PRIMARY KEY, the best option if I use [CODE] column to look up the table? This all depends on a great many factors, some of which I have already mentioned but will …
Should a composite primary key out of 3-4 attributes or a unique ...
Dec 3, 2018 · Should a composite primary key out of 3-4 attributes or a unique artificial ID should be used for the situation below? Ask Question Asked 7 years, 2 months ago Modified 7 years, 2 months …
Differences between "Unique Key" and "Primary Key"
Mar 26, 2012 · Primary Key: Purpose of Primary Key is to act as a “KEY”. A primary key is a key in a relational database used to identify records. Unique Index: Unique Index is an “INDEX” intended for …
When should a primary key be declared non-clustered?
Nov 11, 2011 · Having a clustered index key with this low selectivity key as the leftmost key, e.g. , often makes sense because of ranges scans that look for all entries in a particular 'state'. One last note …
Violation of PRIMARY KEY constraint in SSMS import/export wizard
Oct 15, 2020 · Violation of PRIMARY KEY constraint in SSMS import/export wizard Ask Question Asked 5 years, 3 months ago Modified 2 years, 8 months ago
sql server - BULK INSERT continue on PRIMARY KEY error - Database ...
Oct 21, 2020 · Violation of PRIMARY KEY constraint 'PK__id__790FF7A****'. Cannot insert duplicate key in object 'dbo.activity'. The duplicate key value is (1234) This gets quite cumbersome when …