####1.About how to remove a foreign key in a table(MySQL):
find the constraint: show create table TABLE_NAME;From this request you can see the CONSTRAINt of the foreign key, it’s a sequence like “FK84229236324DD57”
alter table user_radius_attribute drop foreign key FK84229236324DD57this command removes the foreign key
c, if removing a primary key, the command is
alter table user_radius_attribute drop key FK84229236324DD57
####2. ExtJs Array different method comparing
Extjs has a few methods to loop an Array, which are quite similar yet still have differences.
forEach(): loop the whole elements of the array, just like for-loop
every(): loop the whole elements of the array, but stops looping the first time the iterator returns false or something falsy
some(): loops and stops looping the first time the iterator returns true or something truthy
filter(): creates a new array including elements where the filter function returns true and omitting the ones where it returns false
map(): creates a new array from the values returned by the iterator function
reduce(): builds up a value by repeated calling the iterator, passing in previous values; see the spec for the details; useful for summing the contents of an array and many other things
reduceRight(): like reduce, but works in descending rather than ascending order
- d, The way grails to avoid the xss attack:
<meta content="width=device-width, initial-scale=1.0" name="viewport"/>This sentence in html file tells browser to adjust width just to comply with the screen width.