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I have a sqlite database from which I want to extract a column of information with the datatype BLOB. I am trying this:
SELECT cast(data as TEXT) FROM content
This is obviously not working. The output is garbled text like this:
x��Uak�0�>�8�0Ff;I�.��.i%�A��s�M
The data in the content column is mostly text, but may also have images (which I recognized could cause a problem if I cast as TEXT). I simply want to extract that data into a usable format. Any ideas?
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If you want to update the BLOB datatype column to the TEXT datatype column. Follow these steps: Alter the table and add a column having data type TEXT. Add content to that column after converting BLOB data to TEXT date.
The four BLOB types are TINYBLOB , BLOB , MEDIUMBLOB , and LONGBLOB . These differ only in the maximum length of the values they can hold. The four TEXT types are TINYTEXT , TEXT , MEDIUMTEXT , and LONGTEXT . These correspond to the four BLOB types and have the same maximum lengths and storage requirements.
(10) Does SQLite support a BLOB type? SQLite allows you to store BLOB data in any column, even columns that are declared to hold some other type. BLOBs can even be used as PRIMARY KEYs.
A BLOB (large binary object) is an SQLite data type that stores large objects, typically large files such as images, music, videos, documents, pdf, etc. We need to convert our files and images into binary data (byte array in Python) to store it into SQLite database.
You can use
SELECT hex(data) FROM content
or
SELECT quote(data) FROM content
The first will return a hex string (ABCD), the second quoted as an SQL literal (X'ABCD').
Note that there's (currently) no way of converting hexadecimal column information back to a BLOB in SQLite. You will have to use C/Perl/Python/… bindings to convert and import those.
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