View source for Working with Multimedia Data

==Working with Multimedia Data==
Multimedia data can be stored in Recital tables in object [[Appendix A|datatype]] fields.  The data is stored in binary large object (BLOB) format in the ''.dbt'' file, with a corresponding pointer in the table record.

Recital provides the following functions to handle the transfer and querying of multimedia data:

* [[OBJECTREAD()|objectread()]] - read a binary file into a Recital object field
* [[OBJECTWRITE()|objectwrite()]] - write the contents of a Recital object field to a binary file
* [[OBJECTTYPE()|objecttype()]] - return the type of a Recital object field, e.g. ''jpg'' 

===Inserting Multimedia Data===
<pre>
objectread(<filename as character>,<fieldname as character>)
</pre> 

The [[OBJECTREAD()|objectread()]] function reads an external binary file into a Recital object field. It returns true (.T.) if the operation was successful, and false (.F.) otherwise.

The file to read in is specified in <filename>, and can be any valid Recital expression that returns a valid file name.  The first three characters of the file extension are stored in the object field as the object's type, as returned by the [[OBJECTTYPE()|objecttype()]] function.

The field into which the file is placed is specified in <object field>, and must be a Recital object field in the currently selected workarea.

'''Example'''

<code lang="recital">
open database southwind
use categories
objectread("newpic.jpg",picture)
close databases
</code>


===Retrieving Multimedia Data===

<pre>
objectwrite(<filename as character>,<fieldname as character> [, <tempfile as logical>])
</pre> 

The [[OBJECTWRITE()|objectwrite()]] function writes an external binary file from a Recital object field. The objectwrite() function returns true (.T.) if the external binary file was created successfully, and false (.F.) otherwise.

The name of the file to create can be specified in the parameter <filename>.  This can be any valid Recital expression that returns a valid filename.  The filename can also be an empty string, providing that the logical expression <expL> is true (.T.).  In this case, a unique temporary file name will be generated and the object written to this file, with the file name being returned from objectwrite().

The Recital object field containing the data to be written, is specified in the parameter <object field>, and must be a valid field in the currently selected workarea.

'''Example'''

<code lang="html">
<%
open database southwind
use categories
scan
m_file = "__"+ltrim(str(recno()))+".jpg"
? '<img src="'+objectwrite(m_file,picture,.t.)+'"><br>'
endscan
close databases
%>
<body bgcolor="#FFFFFF" text="#000000">
</body>
</code>