PostgreSQL tutorial

PostgreSQL, often referred to as Postgres, is an advanced open-source object-relational database management system (ORDBMS). PostgreSQL is known for its stability, reliability, and feature-richness, making it a preferred choice for many developers and organizations.

PostgreSQL is written in the C programming language and offers extensive support for various programming languages, including SQL, Python, Java, and many others. It adheres to the SQL standards and provides a robust set of features for managing and manipulating data. Additionally, PostgreSQL supports various advanced features such as complex queries, indexes, transactions, and concurrency control mechanisms, which contribute to its reputation as a powerful and flexible database system.

Features of PostgreSQL

One of the notable features of PostgreSQL is its support for object-relational database capabilities. It allows users to define their custom data types, operators, and functions, making it possible to store and query complex data structures. This flexibility enables developers to build sophisticated applications that go beyond traditional relational database models.

PostgreSQL also provides extensive support for geographic data, making it a popular choice for applications involving location-based services. It includes advanced features like geometric data types, spatial indexing, and spatial functions, enabling efficient storage and querying of geospatial information.

Another strength of PostgreSQL is its focus on data integrity and reliability. It offers a wide range of constraints, triggers, and rules to enforce data integrity rules and maintain consistency. Furthermore, PostgreSQL provides support for ACID (Atomicity, Consistency, Isolation, Durability) properties, ensuring reliable and transactional data processing.

PostgreSQL’s extensibility is another feature that sets it apart from other databases. It allows users to create custom extensions, which can be used to enhance the functionality of the database system. These extensions can add new data types, functions, or even integrate with external libraries, expanding the capabilities of PostgreSQL to meet specific application requirements.

In terms of scalability, PostgreSQL offers various features to handle large datasets and high loads. It supports table partitioning, allowing data to be distributed across multiple storage units for efficient retrieval. Furthermore, PostgreSQL supports asynchronous and synchronous replication, which enables the setup of high availability and fault-tolerant database clusters.

In PostgreSQL are four procedural languages with you can write functions:

PL/pgSQL
PL/Tcl
PL/Perl
PL/Python

This postgresql tutorial will be concentrated on PL/pgSQL language.

1. Introduction to PostgreSQL

• PostgreSQL Create Table – shows you how to create table in a PostgreSQL database.
• PostgreSQL Insert – insert rows into a table from a PostgreSQL database.
• PostgreSQL Select – returns rows from a table.
• PostgreSQL Update – change the value of the columns in a table.
• PostgreSQL Delete – delete rows from a table.

2. Conditional Statements

• PostgreSQL IF – example of the IF statement.
• PostgreSQL IF – Else – example of the IF – Else statement.
• PostgreSQL IF – Elsif – Else – learn how to use conditional statements.
• PostgreSQL Case – example of the CASE statement.
• PostgreSQL LOOP – example of the LOOP statement.

3. Create Function

• PostgreSQL Create Function – shows you how to create function in the PostgreSQL database.

4. Create Trigger

• PostgreSQL Create Trigger – syntax and example of how to create trigger in the PostgreSQL database.

5. View

• PostgreSQL View – syntax and example of how to create and use a view.

6. Aggregate functions

• PostgreSQL AVG – returns the average in a select statement.
• PostgreSQL MAX – returns the maximum value in a select statement.
• PostgreSQL MIN – returns the minimum value in a select statement.
• PostgreSQL SUM – returns the sum value of all rows in a select statement.

7. PostgreSQL Tutorial

• PostgreSQL Tutorial – basic commands of PostgreSQL language.

PL/pgSQL – SQL Procedural Language

The basic commands of PL/pgSQL – SQL Procedural Language:

• PostgreSQL Create Table
• PostgreSQL Drop Table
• PostgreSQL Select
• PostgreSQL Insert
• PostgreSQL Update
• PostgreSQL Delete
• PostgreSQL Distinct
• PostgreSQL Where
• PostgreSQL And – Or
• PostgreSQL Between
• PostgreSQL Like
• PostgreSQL Order By
• PostgreSQL Group By
• PostgreSQL Having
• PostgreSQL Count
• PostgreSQL AVG
• PostgreSQL MAX
• PostgreSQL MIN
• PostgreSQL SUM
• PostgreSQL View
• PostgreSQL Create Function
• PostgreSQL Create Trigger

Alter Examples

• Add primary key to existing table
• Add foreign key constraint to table
• Add unique key constraint to table
• Add column to existing table
• Add multiple columns to existing table
• Drop column from existing table
• Drop multiple columns from table
• Rename column table
• Rename name of existing table
• Add check constraint to a table
• Remove check constraint from table

PostgreSQL error messages help

• Error messages help
• Column must appear in the GROUP BY clause
• Column specified more than once
• Constraint for relation already exists
• Constraint of relation does not exist
• Control reaches end of function without return
• ERROR: cannot begin/end transactions in PL/pgSQL
• Duplicate key value violates unique constraint
• Duplicate key value violates NOT NULL unique constraint
• INSERT has more target columns than expressions
• Invalid input syntax for type boolean
• Multiple primary keys for table are not allowed
• Negative substring length not allowed
• Null value in column violates not-null constraint
• PostgreSQL Numeric field overflow
• Relation does not exist
• Value too long for type character varying or type numeric

Overall, PostgreSQL is a powerful, feature-rich, and reliable database system that excels in handling complex data and providing robust data management capabilities. Its flexibility, extensibility, and adherence to standards make it an excellent choice for a wide range of applications, from small-scale projects to enterprise-level systems.