Database Toolbox cannot store vectors or strings

I'm trying to store and retrieve data in an SQLite database with Matlab's Database toolbox. When I try to store strings or vectors as directed by the documentation and then retrieve them I get NaN instead. Additionally, the data should come back as a table but instead, it comes back as a numeric matrix (which may explain the NaN?).

Here is the code:

% create a database from scratch (this is the only documented method I could find)
dbfile=fullfile('test_database.db');
conn=sqlite(dbfile,'create');
close(conn); % this type of interface can be useful but cannot handle null data
% and is not very feature rich

% now we connect to and populate the actual database 
% (requires installing a driver first)
conn=database('SQLite','','','org.sqlite.JDBC',['jdbc:sqlite:',dbfile]);

% allow foreign keys so one table can link to other tables
curs=exec(conn,'PRAGMA foreign_keys=ON');

% create a table to store things
create_test_table=['create table test_table (testID NUMERIC PRIMARY KEY,',...
    ' test_string VARCHAR, test_vector NUMERIC, test_scalar NUMERIC)'];
curs=exec(conn,create_test_table);

% create a new record
datainsert(conn,'test_table','testID',1)

% add data to that record
where_clause=['WHERE testID = ',num2str(1)];
update(conn,'test_table','test_string',{'string1'},where_clause)
update(conn,'test_table','test_vector',{[1,2,3,4]},where_clause)
update(conn,'test_table','test_scalar',1,where_clause)

% now view the data
sqlquery='SELECT * FROM test_table';
data_to_view=fetch(conn,sqlquery)
% same thing happens with this command
% %         curs=exec(conn,sqlquery)
% %         curs=fetch(curs)
% %         curs.Data

ACTUAL RESULT:

data_to_view =

       1   NaN   NaN     1

EXPECTED RESULT (given the documentation https://www.mathworks.com/help/database/ug/fetch.html):

data_to_view =

    1×4 table

         testID        test_string      test_vector    test_scalar    
      _____________    ___________    ______________    ________    

           1            'string1'       1x4 double         1

The following also returns NaN:

sqlquery='SELECT test_string FROM test_table';
data_to_view=fetch(conn,sqlquery)