This blog will focus on PostgreSQL and its uniqueness in comparison to other open-source SQL programs. Let’s look at PostgreSQL Common Table Expressions, PostgreSQL Upsert and Update+Insert.
Introduction to PostgreSQL
PostgreSQL, a relational database management software, is enterprise-class and open-source. PostgreSQL allows for both relational and nonrelational data queries. It is a robust database that has been developed by the open-source community for more than 20 years.
Many apps, both online and mobile, use PostgreSQL for their primary database.
PostgreSQL’s top features
PostgreSQL offers many advanced features that aren’t available in other enterprise-class databases management systems such as:
Types you can declare
Inheritance in tables has been a concept for a while.
Locking mechanism with sophisticated design
Foreign keys have integrity as references
Subquery, views, rules
Transactions that are linked together (save point)
PostgreSQL’s key feature is extensibility. PostgreSQL allows us to create data types, indexes, and functional languages.
We can always create a custom plugin to fix any issues with the system, such as adding an optimizer or a new optimizer.
Uniqueness of PostgreSQL
PostgreSQL can be used as an object-relational database. It is superior to MySQL, MariaDB, Firebird, and Firebird, all open source SQL databases. It supports many data types, as shown below:
JSON support: PostgreSQL’s JSON support allows you to use an SQL database without a schema. This is useful when the data structure needs some flexibility because of ongoing development or when the fields that the data object will contain are not known. JSON data types enforce proper JSON. This allows you to query and manipulate data using the JSON functions and operators included in PostgreSQL.
Geometric Data: Geometric data is rapidly becoming a requirement in many applications. PostgreSQL has long supported geometric data types like points, lines and circles. One of these data types is the PATH data type. A path is a series or points that can be either open (the starting point and end point are not connected) OR closed (the end points and beginning are connected).
Network Address: PostgreSQL can store different types of network addresses. The CIDR data type (Classless Internet Domain Routeting) follows the IPv4/IPv6 network address conventions. Accessible for network address storage is the INET data type. This is for IPv4 hosts and IPv6 hosts that have an optional subnet. You can store MAC addresses using the MACADDR data type.
PostgreSQL CTE
CTE (Common Table Expression), is a temporary result set that PostgreSQL allows the user to reference in another SQL operation, such as SELECT or INSERT. CTEs are temporary because they only exist while the query execution is taking place. CTEs in PostgreSQL are often used to simplify complex joins or subqueries.
Syntax:
With CTE_Name (Column_list) as (CTE_query_statement)Statement;1234With CTE_Name (Column_list) as (CTE_query_statement)Statement;The CTE’s name comes first, followed by an optional column list.
Second, you must specify a query that returns a set of results within the WITH clause. The CTE query definition’s select lists will be used to determine the CTE’s column listing if you don’t mention it.
Third, treat CTE as a view or table in the SELECT/INSERT/UPDATE or DELETE statements.
Example:
With cte_insert (Insert in Students(id.name) values (1.’Ravi’) returning ID) Select * from students where id= (select the id form cte_insert).
Executing multiple qu