You can use the json_object_keys function to extract the keys (field names) from a JSON object in PostgreSQL database. This function takes a JSON object as its argument and returns a set of text values representing the keys in the JSON object. Here is the basic syntax for the json_object_keys function: sqlCopy code json_object_keys(json_object) where…
The json_agg function is used to aggregate values into a JSON array in PostgreSQL database. It takes one or more values and returns a JSON array that contains those values as elements. This function is particularly useful when you want to combine rows or values into a single JSON array in the result of a…
The json_populate_recordset function is used to populate a set of composite records from an array of JSON objects. This is useful when you have an array of JSON objects, and each object corresponds to a record in a composite type. Below is the basic syntax of the json_populate_recordset function: json_populate_recordset(base_type anyelement, from_json_array json) -> SETOF…
The json_extract_path_text function is used to extract a specific value from a JSON object or array by specifying a path to the desired element. This function returns the value as text. The basic syntax of the json_extract_path_text function is as shown below: json_extract_path_text(json_object_or_array, path_element1, path_element2, …, path_elementN) Here’s an example of using the json_extract_path_text function:…
In PostgreSQL, you can write stored procedures, functions, and triggers using various programming languages. PostgreSQL supports multiple procedural languages, including: When you create a function or procedure in PostgreSQL, you can specify the language you want to use, and then write the code accordingly. Here’s a basic example of creating a function using PL/pgSQL: sqlCopy…
You can refresh the data in a materialized view using the REFRESH MATERIALIZED VIEW statement in PostgreSQL database. A materialized view stores a snapshot of the data from the underlying tables, and this data can become stale over time. The REFRESH MATERIALIZED VIEW command allows you to update the materialized view with the latest data…
You can drop (delete) a materialized view using the DROP MATERIALIZED VIEW statement in PostgreSQL database. Here’s the basic syntax: DROP MATERIALIZED VIEW IF EXISTS view_name; where Here’s an example of dropping a materialized view named total_sales_by_product: DROP MATERIALIZED VIEW IF EXISTS total_sales_by_product; Make sure you exercise caution when using the DROP statement, as it…
Creating a materialized view in PostgreSQL involves using the CREATE MATERIALIZED VIEW statement. A materialized view is a precomputed and stored view of the data from one or more tables. Using materialized views can improve query performance by reducing the need to repeatedly compute the same complex queries. Here’s the basic syntax for creating a…
You can disable a user account in PostgreSQL database by revoking their login privileges. Disabling a user prevents them from connecting to the PostgreSQL database server. Here’s the basic syntax to revoke login privileges from a user globally: ALTER USER username NOLOGIN; Where username is the name of the user you want to lock/disable. By…
You can rename a view using the ALTER VIEW statement with the RENAME TO clause in PostgreSQL database. Renaming a view can be useful when you want to change its name to something more meaningful or descriptive. Here’s the basic syntax for renaming a view: ALTER VIEW old_view_name RENAME TO new_view_name; where old_view_name is the…