WEEK 3 Flashcards
Metadata
Metadata tells you where the data comes from, when and how it was created, and what it’s all about.
A relational database
Is a database that contains a series of related tables that can be connected via their relationships.
2 types of keys in a relationnal databases
Primary Key
Foreign Key
A primary key
Is an identifier that references a column in which each value is unique.
A primary key is used to ensure data in a specific column is unique.
It uniquely identifies a record in a relational database table.
Only one primary key is allowed in a table and they cannot contain null or blank values.
A foreign key
Is a field within a table that’s a primary key in another table.
And a foreign key is a column or group of columns in a relational database table that provides a link between the data and two tables.
It refers to the field in a table that’s the primary key of another table.
Lastly, it’s important to note that more than one foreign key is allowed to exist in a table.
Metadata
Metadata helps data analysts interpret the contents of the data within a database.
Metadata tells the who, what, when, where, which, how, and why of data.
Metadata creates a single source of truth by keeping things consistent and uniform.
Metadata also makes data more reliable by making sure it’s accurate, precise, relevant, and timely.
Descriptive metadata
Is a metadata that describes a piece of data and can be used to identify it at a later point in time.
For instance, the descriptive metadata of a book in a library would include the code you see on its spine, known as a unique International Standard Book Number, also called the ISBN.
Structural metadata
Which is metadata that indicates how a piece of data is organized and whether it’s part of one or more than one data collection.
An example of structural data would be how the pages of a book are put together to create different chapters.
Administrative metadata
Is metadata that indicates the technical source of a digital asset.
When we looked at the metadata inside a photo, that was administrative metadata. It shows you the type of file it was, the date and time it was taken, and much more.
A metadata repository
Is a database specifically created to store metadata.
It can be stored in a physical location, or they can be virtual, like data that exists in the cloud.
metadata repositories
Metadata repositories make it easier and faster to bring together multiple sources for data analysis.
They do this by describing the state and location of the metadata, the structure of the tables inside, and how data flows through the repository.
They even keep track of who accesses the metadata and when.
Data governance
Is a process to ensure the formal management of a company’s data assets.
