Retrieve blob field from mySQL database with MATLAB

Posted by yuk on Stack Overflow See other posts from Stack Overflow or by yuk
Published on 2010-04-15T17:34:45Z Indexed on 2010/04/15 18:33 UTC
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I'm accessing public mySQL database using JDBC and mySQL java connector. exonCount is int(10), exonStarts and exonEnds are longblob fields.

javaaddpath('mysql-connector-java-5.1.12-bin.jar')
host = 'genome-mysql.cse.ucsc.edu';
user = 'genome';
password = '';
dbName = 'hg18'; 
jdbcString = sprintf('jdbc:mysql://%s/%s', host, dbName);
jdbcDriver = 'com.mysql.jdbc.Driver';
dbConn = database(dbName, user , password, jdbcDriver, jdbcString);
gene.Symb = 'CDKN2B';
% Check to make sure that we successfully connected
if isconnection(dbConn)
    qry = sprintf('SELECT exonCount, exonStarts, exonEnds FROM refFlat WHERE geneName=''%s''',gene.Symb);
    result = get(fetch(exec(dbConn, qry)), 'Data');
    fprintf('Connection failed: %s\n', dbConn.Message);
end

Here is the result:

result = 
    [2]    [18x1 int8]    [18x1 int8]
    [2]    [18x1 int8]    [18x1 int8]

result{1,2}'
ans =
   50   49   57   57   50   57   48   49   44   50   49   57   57   56   54   55   51   44

This is wrong. The length of 2nd and 3rd columnsshould match the number in the 1st column.

The 1st blob, for example, should be [21992901; 21998673]. How I can convert it?


Update:

Just after submitting this question I thought it might be hex representation of a string. And it was confirmed:

>> char(result{1,2}')
ans =
21992901,21998673,

So now I need to convert all blobs hex data into numeric vectors. Still thinking to do it in a vectorized way, since number of rows can be large.

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