Find bottlenecks in Firebird database

How to convert BLOB to string?


Direct conversion is not possible without using some UDF, but you can extract text using SUBSTRING function:

DECLARE VARIABLE c1 VARCHAR(32000);
SELECT SUBSTRING(blob1 FROM 1 FOR 32000) FROM t1 INTO c1;

Please note that maximum length for VARCHAR is 32767 bytes (which might be less characters in multi-byte character sets like UTF8).

Various database access layers also have ability to retrieve BLOB data as string. For example, in PHP you could use:

$row = ibase_fetch_assoc($qry, IBASE_TEXT);

This automatically converts all textual BLOBs to VARCHARs, so you don't need to fetch blobs writing specific PHP code.


Do you find this FAQ incorrect or incomplete? Please e-mail us what needs to be changed. To ensure quality, each change is checked by our editors (and often tested on live Firebird databases), before it enters the main FAQ database. If you desire so, the changes will be credited to your name. To learn more, visit our add content page.

If you are a commercial tool maker and your tool features a great way to handle the issue written about in this FAQ, please check out our advertisement page.



All contents are copyright © 2007-2014 FirebirdFAQ.org unless otherwise stated in the text.


Links   Firebird   News   FlameRobin   Home Inventory powered by FB  
Add content   Advertise   About  

Categories
 Newbies
 SQL
 Installation and setup
 Backup and restore
 Performance
 Security
 Connectivity and API
 HOWTOs
 Errors and error codes
 Miscellaneous