What are the features of PostgreSQL?

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What are the features of PostgreSQL?

PostgreSQL feature highlights

  • User-defined types.
  • Table inheritance.
  • Sophisticated locking mechanism.
  • Foreign key referential integrity.
  • Views, rules, subquery.
  • Nested transactions (savepoints)
  • Multi-version concurrency control (MVCC)
  • Asynchronous replication.

What is DESC in PostgreSQL?

When sorting your result set in descending order, you use the DESC attribute in your ORDER BY clause as follows: SELECT last_name, first_name, city FROM contacts WHERE first_name = ‘Joe’ ORDER BY last_name DESC; This PostgreSQL ORDER BY example would return all records sorted by the last_name field in descending order.

How do I run a PostgreSQL function?

The use of assignments and SELECT statements to execute functions is standard in PL/pgSQL because all functions in a PostgreSQL database must return a value of some type. Use the PERFORM keyword to call a function and ignore its return data. Example 11-50 shows the syntax of the PERFORM keyword.

Who uses Postgres?

5124 companies reportedly use PostgreSQL in their tech stacks, including Uber, Netflix, and Instagram.

  • Uber.
  • Netflix.
  • Instagram.
  • Spotify.
  • Instacart.
  • Robinhood.
  • Twitch.
  • reddit.

What are the advantages of PostgreSQL?

PostgreSQL’s Strength

  • Open Source DBMS.
  • Diverse Community.
  • Function.
  • ACID and Transaction.
  • Diverse indexing techniques.
  • Flexible Full-text search.
  • Diverse kinds of replication.
  • Diversified extension functions.

How do you describe a table in PostgreSQL pgAdmin?

PostgreSQL DESCRIBE TABLE using pgAdmin 4

  1. SELECT COLUMN_NAME.
  2. FROM information_schema. COLUMNS.
  3. WHERE TABLE_NAME = ‘customer’;

How does a function in PostgreSQL work?

PostgreSQL function or stored procedure is nothing but a set of SQL statements stored on the database server and invoked after using a SQL interface. Create a statement is used to create a new function in it. We can implement this function in any languages like C, Python and pl/pgsql.

What does the window attribute mean in PostgreSQL?

For backward compatibility, the name can be enclosed by single quotes. WINDOW indicates that the function is a window function rather than a plain function. This is currently only useful for functions written in C. The WINDOW attribute cannot be changed when replacing an existing function definition.

When to use the as keyword in PostgreSQL?

The AS keyword is used for creating a standalone function. plpgsql is the name of the language that the function is implemented in. Here, we use this option for PostgreSQL, it Can be SQL, C, internal, or the name of a user-defined procedural language. For backward compatibility, the name can be enclosed by single quotes.

What are the argument types in PostgreSQL create function?

The argument types can be base, composite, or domain types, or can reference the type of a table column. Depending on the implementation language it might also be allowed to specify “pseudotypes” such as cstring. Pseudotypes indicate that the actual argument type is either incompletely specified, or outside the set of ordinary SQL data types.

How to create function in PostgreSQL?

In PostgreSQL, if we want to specify a new user-defined function, we can use the CREATE FUNCTION command. Syntax of PostgreSQL CREATE Function command The Syntax for PostgreSQL CREATE Function command is as follows: CREATE [OR REPLACE] FUNCTION function_name (arguments)

What are the benefits of using the Postgres database?

Benefits Performance and scalability. In larger database systems where data authentication and read/write speeds are essential, PostgreSQL is hard to beat. Concurrency support. Deep language support. Business continuity. 100% open source.

Who is using Postgres?

PostgreSQL is one of the most popular and widely used database systems in the world. Companies who use PostgreSQL include Apple, Cisco, Fujitsu, Skype and IMDb. You will learn how to: Retrieve data from database tables using SQL SELECT queries.

How to query date and time in PostgreSQL?

How to Query Date and Time in PostgreSQL. Get the date and time time right now: select now(); — date and time select current_date; — date select current_time; — time. Find rows between two absolute timestamps: select count (1) from events where time between ‘2018-01-01’ and ‘2018-01-31’