Beginner's Guide to PostgreSQL

In sthis video, we'll start pgAdmin III - the client application we'll use to connect to, manage and manipulate our databases, and connect to our local database server, that we installed in the previous step.

When you open pgAdminIII for the first time, it should have you're local server in the servers list. In this video, I'll show you how to register a server in the list, in case your local server is not available or if you wish to connect to a remote server.

By default, the server installation won't allow you to connect to the databases from external computers - only the local machine is allowed.

To allow other computers to connect, you need to edit the pg_hba.conf, and open a firewall port. This video shows you how.

Note:

Around minute 4, I mention the CIDR notation. For more details and a cheat sheet for CIDR netmask notation, check out: http://www.oav.net/mirrors/cidr.html

In this vídeo, I'll show you how to create a database through pgAdmin III. The process only requires you give your new database a name, but there are other options that are available and usefull, and I analyse them in this video.

In this video we'll look at how tables are created in pgAdmin III and the options available for the table.

In this video, I show you how to add, edit and delete records in a table, and also how to use the table's ordering and filtering options, within pgAdmin III.

PostgreSQL suports multiple data types for its columns and choosing the right datatype for each column is importante, both for correct data representation and database optimization. This lesson is just a short video to set the stage for the next few clips.

Postgres offers a series of datatypes to eficiently store numbers in diferent  formats and ranges. In this video I review the numeric types and show some examples of how rounding decimal numbers works, and some errors that may occur.

Here We talk about how the serial and bigserial types work in creating record IDs in our tables.

In Postgres, 3 datatypes are available to store character-based information: char(n), varchar(n) and text. In this video I go over their diferences.

There are a few datatypes we can use for date and time information. In this video we look at the date type

We can use the time type to store time information, without dates. This video shows how to write the times into a tables field and some variations of the notation

Uou can combine date and time in the same field using the timestamp datatype. It also allows the storage of timezone data, essential to any aplication that crosses timezones.

The boolean datatype allows us to store eaither a true or false value. It is very comun to use it to store data that answers true/false or yes/no questions.

The NULL value allows us to meaningfully indicate that a certain field's data is unkown, and a better option to inserting fake or misleading default values.

The requirments gathering process is important in database construction since it allows for a better understanding of the problem that our databse will solve. In this video, we present requirements for our car repair shop database, to be used in the next few videos.

This PDF contains the set of slides used to define the requirements for our database. 

In this video, we go through the client part of requirements and design our database tables. We transform requirements into tables, columns and relationships.

In this second part, we design the tables to store data for our repair shop's interventions on vehicles. 

In this video we choose the datatypes for our columns, based on what they will contain.

This PDF contains the table definitions from the last set of videos. Use it to follow along the database creation in pgAdmin III

When creating tables, we need to start off with those that don't have any dependencies - that is, that have no foreign keys to other tables. Creating these first avoids any problems defining the foreign key constraints on the tables.

Constraints are rules we apply to our tables' columns in order to garantee that certain rules are followed when we enter data. Will take a look at the constraints Postgres allows in this video.

The next set of tables we create will have foreign keys so we need to create the table and while doing so, establish the relationship with the table that we will be referencing.

In this video, we finish creating the car repair shop database by building the remaining three tables.

We can create new users (called roles, within PG) to control how users access the database. There are a few steps you need to take in Postgres to correctly create new users. Ins this lesson, I cover those steps so that a new user can connect to a specific database and access it with the necessary privileges.

Database backups are very important in avoiding data loss due to system failures, harddrive failures and even human error. Postgres comes with a couple of aplications that allow us to backup a database (pg_dump) and restore a backup (pg_restore). We can access and manage the options through pgAdmin III. In this video I show you how to backup and restore a database.

This video is an overview of what will be covered in this third module.

In this video we look at the CREATE TABLE command, and use it to build a very simple version of the carBrand table. No constraints are aplied to the table - it is ment to understande the basic sintaxe and structure of the statement.

In this video, we will recreate the carBrand table, but we'll add the PRIMARY KEY constraint to the id column, and NOT NULL and UNIQUE constraints to the name column in the SQL statement.

We'll also create the client table, and add a default value to a column in that table.

In this video , we build the remaining two tables with no foreign keys in the RepairShop database.

I'll show you how to execute multiple statements in the same run, add check constraints, and also look at an anlternative notation for the column and constraint organization of the CREATE TABLE command.

You can use the SQL statements in this file to quickly execute the steps I take in the previous video.

In this table we look at creating tables with foreign key constraints and the notation variations associated to it.

In this video we create the rest of the tables that have foreign key references. I also introduce comments and selective execution of the script.

In thsi video we look at the DROP TABLE and DROP TABLE... CASCADE command and also how to save and recall queries in the query editor.

The ALTER TABLE command allows us to edit our data structure: we can create or drop new columns, alter datatpyes and constraints or even modify existing constraints.

In this video we create a blank table (partAdded) that is missing in our database, and create the missing columns using the ALTER TABLE command.

ERRATA:

I made a couple of mistakes in this clip. First, the third colum created in the video is "vehicle_id" but should have been "intervention_id" and reference the intervention table. Second, the check constraint on the cost column should have been ">=". The error are highlçighted in the video.

The INSERT INTO SQL Command allows us to insert rows of data into our database tables. This video shows you how to build basic insert statements that insert one or more rows into the table.

Note: When I refer to quotation marks, I sometimes don't indicate if they are single or double. So, for table names or column names that have capital letters, you need to use double quotes, while for string values, you use single quotes.

You can use the SQL statements in this file to quickly execute the steps I take in the previous video.

Includes The Insert statement to add clients to the table and the update statements used in the video

In this lesson, I talk about the DELETE FROM statement and show how to use it to delete specific rows or all the rows from a table.

Typicly, deleting data from a table only afects the data in that tabel. When dealing with tables that are references for foreign keys, you can't delete data without deleting all the dependant elements.

In this video, we see how to build delete statements to handle multiple tables with dependant data and how to use the ON DELETE CASCADE clause in foreign key constraints.

The file contains the script used in the delete from command videos.

The TRUNCATE command allows us to quickly delete all the rows in a table and CASCADE the deletes to related tables. We can also use a "Restart Identity" clause to reset the sequence that sets the primary key's value.

The script used in the previous TRUNCATE command video.

Before we procede to hte next set of videos, where we will be executing SELECT commands, It is important that we add data to the database. I've provided a script file that adds data, which you can download from the next lesson. In this video, I show you how to use the file to insert data into the database.

Before we procede to the next set of lessons, it is important to insert data into the database to be able to create meaningfull SELECT statements. Use the provided script file to add data to the database.

This video is the first in a series of clips whare we work on selecting data. We start by analysing the basic components of a query.

We have a look at the grafical query builder in pgAdmin that lets you create queries in a drag n' drop style of editing.

The WHERE clause in the select statement allows us to filter the data that the query returns, generating precise result sets. In this video we look at how we can create expressions in the where clause.

In this video we look at the BETWEEN and IN operatores and their use in WHERE clauses to filter data through ranges or sets of values.

We can't use the equal sign or not equal sign in our statements to compare with NULL since NULL represents no data. To use NULLs in a statement correctly We need to use the IS or IS NOT keywords. 

Pattern matching is an important form of filtiring, especially when working with strings. Being able to match a part of a string can become a simple yet powerful mechanism for search. In this video we look at the various forms of the LIKE operator in the WHERE clause.

We can build queries that have a WHERE clause, using the graphical query builder. In this video I show you how to compose those queires using diferent types of criterias.

This file contains the various SELECT statements used in the previous vídeos.

LIMIT and OFFSET allow us to create a paging mecanism in our queries - LIMIT limits the number of rows returned, while OFFSET allows us to skip rows from the beginning of the full set. In this video I'll show you some examples of how this is implemented in a SELECT statement.

The ORDER BY clause allows us to order the results by a set of columns. Orderingcan be ascending (ASC) or descending (DESC), and some care must be taken when handling NULL values. In this video, I show some examples of how to use the ORDER BY clause in select statements.

This file has the SQL statements used in the Order by video, to help you follow allong and test the commands.

Aggregate functions are a powerful SQL mechanism that allows you to compute values on result sets from your select queries.