Bonus Tip 1: How to Describe Postgres Schemas Using psql? A schema in Postgres is like a container that allows us to organize the database objects into logical groups. Postgres allows us to create several schemas in a single database. Each schema can have its own set of objects like tabl...
Step 3: Describe a Table Let’s run the“\d”command followed by the table name to see all the columns present in the selected table: \d staff_details; Step 4: Rename the Column Suppose we have to rename the“staff_location”column to“staff_address”. Execute the“RENAME COLUMN”comman...
Also, we have used a join condition to update the rows from the table. We have used two tables with join conditions to update rows in PostgreSQL. Examples Below is an example of an update statement as follows. We are using stud1 and stud2 tables to describe the example of the update s...
In this article, we will describe theunnest()keyword and its uses in PostgreSQL with multiple examples. PostgreSQLunnest ()Functionality In PostgreSQL, you can use an array as a data type. There are also multiple functions related to improving the usability of arrays in the language. ...
To begin finding information about the tables in the system, you can simply return columns fromPG_TABLE_DEF: SELECT *FROMPG_TABLE_DEF; For better or worse,PG_TABLE_DEFcontains information abouteverythingin the system, so the results of such an open query will be massive, but should give ...
This article will teach you how to usemysqli_queryto describe a database table. We’ll do the description using theDESCRIBEcommand in SQL. At the same time, we’ll print the result, and it’ll look like what you’ll see on the MySQL console. ...
Now that you know how to connect to the PostgreSQL database system, you can learn some basic Postgres management tasks. First, create a table to store some data. As an example, a table that describes some playground equipment. The basic syntax for this command is as follows: ...
The query matches the pattern in the second example because we used the uppercase string name “ABC”. Examples of Postgres like query Below is an example of a like query in PostgreSQL: We have used the student table to describe the example of a like query in PostgreSQL. The student table...
Learn what a good retention policy is, its benefits for developers, and how to create one in Postgres—including an easier and automatic way.
the server allocates shared memory with a fixed size when it starts. But each PostgreSQL backend process also has to manage private memory to process SQL statements. In this article, I want to describe what amemory contextis, how PostgreSQL uses them to manage its private memory, and how yo...