USE databasecommand sets the default database for your stuff. All operations from that point on are applied to that database. When declaring numeric types, a number in brackets called a width specifier which tells MySQL to pad the field when retrieving it. With floats and decimals a precision parameter can also be specified such as
FLOAT(7,4). Marking a field with the
ZEROFILLattribute will force MySQL to pad the value with zeros.
UNSIGNEDforces only positive numbers.
altercan be used in a number of different ways to change name of fields within a table. If you try to convert field types using
CHANGE, MySQL may result in errors. Try using
IGNOREto get round them.
mysqldumpto backup and restore databases or tables. Delete stuff from databases and tables using