SQL Intro Flashcards
What is SQL
Structured Query Language - programming language designed for working with databases
Data Value
One piece of a record, i.e. a single cell value
Record
A full set of data values, i.e. a row
Field
Column in a table containing specific information about every record in the table
Tabular Data
Data stored on tables
Entity
The smallest unit that can contain a meaningful set of data
Database Designer
Lays the foundation for your system. They will do this by first drawing a Entity-Relationship (ER) Diagram and/or Relational Schema
Entity-Relationship (ER) Diagram
Shows the different entities and their relationships within the system
Relational Schema
An existing idea of how the database must be organized. It is useful if you are certain of the structure/organization of the database you are designing. They are blueprints for databases
Data Manipulation
Using database to extract business insights
Database Management
Refers to all the steps a business manager takes to design, create, and manipulate a database
Database Administration
Daily care and maintenance of the database
Primary Key - what is it and can there be more than one in a table? Do all tables need a primary key?
Column or set of columns whose value exists and is unique for every record in a table. Each table can only have one primary key. Cannot have null values. Not all tables require a primary key.
Foreign Key (FK) - What is it, and can it have repeating and/or null values?
Identifies the relationship between tables, not the tables themselves. Repeating and/or Null values are allwoed
Unique Key - what is it, and can it contain null values? Can there be more than one Unique Key?
Used whenever you want to specify that there should not be duplicate values in a given field, but that that field is NOT a Primary Key. In this case, Null Values are allowed. THere can be more than one Unique Key
