Introduction to PostgreSQL point Data Type

PostgreSQL is an open-source relational database management system that supports various data types, including the point type. The point type is a data type in PostgreSQL used to store points in a two-dimensional Cartesian coordinate system.

Syntax

The point type can be defined using the following syntax:

point(x double precision, y double precision)

Where x and y parameters represent the horizontal and vertical coordinates of the point, respectively. Both parameters must be of double precision data type.

Use Cases

The point type can be used in many applications. Here are some examples:

• Map applications can use the point type to store coordinates of geographical locations.
• Engineering applications can use the point type to store points in designs, such as storing the position of pivot points in structural designs.
• Game applications can use the point type to store coordinates of objects in the game, such as players, monsters, items, etc.

Examples

Example 1

In this example, we create a table called locations with a point column named position. The position column stores the coordinates of each location.

CREATE TABLE locations (
    id SERIAL PRIMARY KEY,
    position POINT
);

Then we insert some data:

INSERT INTO locations (position) VALUES (point(1.0, 2.0));
INSERT INTO locations (position) VALUES (point(3.0, 4.0));

Now, we can query the locations table to retrieve the coordinates of all locations:

SELECT id, position FROM locations;

The result is:

 id |   position
----+--------------
  1 | (1.0,2.0)
  2 | (3.0,4.0)

Example 2

In this example, we create a table called circles with a point column named center. The center column stores the coordinates of the center of each circle.

CREATE TABLE circles (
    id SERIAL PRIMARY KEY,
    center POINT,
    radius DOUBLE PRECISION
);

Then we insert some data:

INSERT INTO circles (center, radius) VALUES (point(1.0, 2.0), 3.0);
INSERT INTO circles (center, radius) VALUES (point(3.0, 4.0), 5.0);

Now, we can query the circles table and calculate the circumference and area of all circles:

SELECT id, 2 * pi() * radius AS circumference, pi() * radius^2 AS area FROM circles;

The result is:

 id | circumference |       area
----+---------------+------------------
  1 |    18.8495559 | 28.27433388230814
  2 |   31.41592654 | 78.53981633974483

Conclusion

The point type is an important data type in PostgreSQL that can store coordinates of points on a plane and be used in various scenarios. Whether it’s storing markers on a map or coordinates of certain locations, the point type can serve these functionalities. However, it’s important to be mindful of the precision of the point type and conversions with other data types when using it. If calculations or comparisons involving point type are needed in queries, dedicated functions and operators provided by PostgreSQL should be used. Overall, the point type is a very useful data type in PostgreSQL that can help users better handle data on a plane.