Mainly differences in NULL or NOT NULL; and UNI vs MUL indexes. 52c52 < aqbasketgroups.billingplace varchar(10) YES --- > aqbasketgroups.billingplace varchar(10) NO 106c106 < aqbudgets.budget_amount decimal(28,6) YES 0.000000 --- > aqbudgets.budget_amount decimal(28,6) NO 0.000000 116c116 < aqbudgets.budget_period_id int(11) YES --- > aqbudgets.budget_period_id int(11) YES MUL 200c200 < auth_subfield_structure.frameworkcode varchar(10) NO --- > auth_subfield_structure.frameworkcode varchar(10) YES 556c556 < default_circ_rules.holdallowed int(1) YES --- > default_circ_rules.holdallowed tinyint(1) YES 631c631 < deletedborrowers.cardnumber varchar(16) NO MUL --- > deletedborrowers.cardnumber varchar(16) YES MUL 660c660 < deletedborrowers.privacy int(11) NO 1 --- > deletedborrowers.privacy int(11) YES 710c710 < deleteditems.stocknumber varchar(32) YES MUL --- > deleteditems.stocknumber varchar(32) YES UNI 807c815 < issues.itemnumber int(11) YES MUL --- > issues.itemnumber int(11) YES UNI 989c997 < message_attributes.message_name varchar(40) NO UNI --- > message_attributes.message_name varchar(40) YES UNI 1352c1391 < suggestions.suggesteddate date NO 0000-00-00 --- > suggestions.suggesteddate date YES