BYTE

The BYTE data type stores any type of binary data, such as images or sounds.

Syntax

BYTE

Usage

A BYTE variable is actually a 'locator' for a large object stored in a file or in memory. The BYTE data type is a complex type that cannot be used like simple types such as INTEGER or CHAR: It is designed to handle a large amount of unstructured binary data. This type has a theoretical limit of 2^31 bytes (~2.14 Gigabytes), but the practical limit depends from the disk or memory resources available to the process. Use the BYTE data type to store, fetch or update the contents of a BYTE database column when using IBM^® Informix^®, or the content of a BLOB column when using another type of database.

Keep in mind that a BYTE variable must be initialized with the LOCATE instruction before usage. You might want to free resources allocated to the BYTE variable with the FREE instruction. A FREE will remove the file if the LOB variable is located in a file.

The LOCATE instruction basically defines where the large data object has to be stored (in file or memory). This instruction will actually allow you to fetch a LOB into memory or into a file, or insert a LOB from memory or from a file into the database.

When you assign a BYTE variable to another BYTE variable, the LOB data is not duplicated, only the handler is copied.

If you need to clone the large object, you can use the I/O built-in methods to read/write data from/to a specific file. The large object can be located in memory, in a specific file or in a temporary file (the temp directory can be defined by the DBTEMP environment variable.

Methods

Table 1. Object methods of the BYTE data type
Name	Description
readFile(`fileName` STRING)	Reads data from a file and copies into memory or to the file used by the variables according to the `LOCATE` statement issued on the object.
writeFile(`fileName` STRING)	Writes data from the variable (memory or source file) to the destination file passed as parameter. The file is created if it does not exist.

MAIN
  DEFINE b BYTE
  DATABASE stock 
  LOCATE b IN MEMORY
  SELECT png_image INTO b FROM images WHERE image_id = 123
  CALL b.writeFile("/tmp/image.png")
END MAIN