How the AsBinary() function works in Mariadb?

The AsBinary() function is a spatial function that returns the binary representation of a given geometry value. The AsBinary() function can be used to convert a geometry value to a binary format that can be stored or transferred more efficiently.

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MariaDB, a popular open-source database, offers a variety of functions to handle geospatial data. Among these is the AsBinary() function, which is essential for converting geometry values into their binary representation. This article will guide you through the syntax, practical examples, and related functions of AsBinary() in MariaDB.

Syntax

The syntax for the MariaDB AsBinary() function is as follows:

SELECT AsBinary(geometry_column) FROM table_name;

The geometry_column should be a column or an expression that returns a geometry type. The function returns the Well-Known Binary (WKB) representation of the geometry.

Examples

Example 1: Basic Usage

To demonstrate the basic usage of AsBinary(), consider the following query:

SELECT AsBinary(Shape) FROM SpatialTable;

This will return the binary representation of the Shape column from SpatialTable.

Example 2: With Literal Geometry

Here’s how you can use AsBinary() with a literal geometry value:

SELECT AsBinary(ST_GeomFromText('POINT(1 1)'));

The output will be the binary form of the given point.

Example 3: In a WHERE Clause

AsBinary() can also be used within a WHERE clause:

SELECT Name FROM Cities WHERE AsBinary(Location) = AsBinary(ST_GeomFromText('POINT(2 2)'));

This query will find cities with the specified location.

Example 4: Combined with Other Functions

Combining AsBinary() with other functions can be very powerful:

SELECT AsBinary(ST_Buffer(Shape, 10)) FROM SpatialTable;

This will return the binary representation of the shapes buffered by 10 units.

Example 5: Inserting Binary Geometry

You can also insert binary geometry data into a table:

INSERT INTO SpatialTable (Shape) VALUES (AsBinary(ST_GeomFromText('LINESTRING(0 0, 1 1, 2 2)')));

This inserts a linestring into SpatialTable.

Here are some functions related to AsBinary() in MariaDB:

  • ST_AsBinary() is a synonym for AsBinary() and works in the same way.
  • ST_GeomFromText() takes a Well-Known Text (WKT) representation of geometry and returns a geometry type.
  • ST_Buffer() returns a geometry that represents all points whose distance from the given geometry is less than or equal to a specified value.

Conclusion

The AsBinary() function is a handy tool for working with binary representations of geometric data in MariaDB. Whether you’re storing, retrieving, or manipulating spatial data, AsBinary() provides a straightforward way to handle binary geometry. Understanding its usage and related functions can greatly enhance your geospatial data management in MariaDB.