From 0f8042c1456b537e67256a5e84f5c75880f086ff Mon Sep 17 00:00:00 2001 From: Nick Leeman Date: Mon, 25 Oct 2021 17:06:27 +0200 Subject: [PATCH] Vault sync: 2021-10-25 17:06:27 --- School/Development/Foreign Key.md | 4 +++- School/Development/Primary Key.md | 6 +++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/School/Development/Foreign Key.md b/School/Development/Foreign Key.md index 15152ff..732f38b 100644 --- a/School/Development/Foreign Key.md +++ b/School/Development/Foreign Key.md @@ -1,4 +1,6 @@ # Foreign Key -A Foreign key is a [[Constraint]] that protects links between tables. +A Foreign key is a [[Constraint]] that protects links between tables. Foreign key is a attribute or attributes that link to the [[Primary Key]] of a other entity set (table). + +For diff --git a/School/Development/Primary Key.md b/School/Development/Primary Key.md index b2c38d0..1b696eb 100644 --- a/School/Development/Primary Key.md +++ b/School/Development/Primary Key.md @@ -1,8 +1,8 @@ # Primary Key -A Primary key is a [[Constraint]] that uniquely identifies [[SQL Database#Entity]] in a entity set (table). +A Primary key is a [[Constraint]] that uniquely identifies [[SQL Database#Entity]] in a entity set (table). Only one pair of values that the primary key forms can exist within a entity set (table). There can only be ONE primary per table and can consist of multiple attributes (columns). -There als o +A primary key is **not** required, but highly advised. Even if you don't use it its better to include one in your schema. -A primary key is **not** required, but highly advised. Even if you don't use it its better to include one in your schema. \ No newline at end of file +## Exaple