What is a View?

In the world of databases, a view is a query that’s stored on a database.

The term can also be used to refer to the result set of a stored query.

To create a view, you write a query, then save it as a view.

To run a view, you query it, just like you’d query a table. The difference is that, the view itself is a query. So when you query the view, you’re effectively querying a query.  This enables you to save complex queries as views, then run simple queries against those views.

Continue reading

What is a Foreign Key?

A foreign key is a field that is linked to another table‘s primary key field in a relationship between two tables.

In relational database management systems, a relationship defines a relationship between two or more tables. That is, the data in one table is related to the data in the other. One table contains the primary key and the other table contains the foreign key.

When we establish a relationship between the tables, we link the foreign key with the primary key. From that point on, any value in the foreign key field should match a value from the primary key field in the other table.

Continue reading

What is a Primary Key?

A primary key is one or more columns that have been configured as the unique identifier field for the table.

Most primary keys are comprised of a single column, but they can also be comprised of multiple columns.

Any value stored in a primary key field is unique to that record. No other record contains that value. The value is a unique identifier.

Continue reading

What is a Relationship?

In relational database design, a relationship is where two or more tables are linked together because they contain related data. This enables users to run queries for related data across multiple tables.

Relationships are a key element in relational database design.

Here’s an example:

Diagram of one-to-many relationship
Example of one-to-many relationship.

In the above example, the City table has a relationship with the Customer table. Each customer is assigned a city. This is done by using a CityId field in the Customer table that matches a CityId in the City table.

While it’s certainly possible to store the full city name in the Customer table, it’s better to have a separate table that stores the city details. You can easily use a query to look up the CityName by using the CityId that’s stored for that customer.

Continue reading

What is an RDBMS?

RDBMS stands for Relational Database Management System.

An RDBMS is a particular type of DBMS that uses a relational model for its databases. An RDBMS therefore enables you to create relational databases.

Relational database management systems have become the most popular type of database system. Most major database management systems are relational. Popular examples include Microsoft Access, SQL Server, Oracle DatabaseMySQL, FileMaker, PostgreSQL, and more below.

Continue reading

How to Create a Database in MySQL Workbench using the GUI

To create a database in the MySQL Workbench GUI:

  1. Click the “new schema” button on the MySQL Workbench toolbar
  2. Enter a schema name (database name) and its default collation and click Apply
  3. Review the SQL statement and click Apply

The database will now be created, and a message will display advising that the script was successful.

Continue reading

How to Create a Table in MySQL Workbench using the GUI

To create a table in the MySQL Workbench GUI:

  1. Under the appropriate database in the left navigation pane, right-click Tables and select Create Table...
  2. Enter the table name, add all column names, their data type, constraints, default values, and any other details as required, then click Apply
  3. Review the SQL statement that will be run against the database and click Apply

The table will now be created, and a message will display advising that the script was successful.

Continue reading