sql - Do I need to issue CREATE INDEX everytime I update the database? -

sql - Do I need to issue CREATE INDEX everytime I update the database? -

i have geo-map database columns of x,y,z,zoom , type. read speed slow when utilize call

select image x = ... , y=... , zoom=... , type =...

thanks kind help stack overflow, found indexing of (x,y,z,zoom) has helped improved read speed impressively.

however, have question create index command need issue 1 time when database initialize @ first time? , database grow gradually, still enjoy read speed improvement brought indexing?

or need issue create index command every time before close application(during application, database grow)?

you need create index once.

the database remember columns index , maintain changing index along table.

if insert entry table, added index. if alter entry - modified in index. finally, if delete entry - removed index.

note, index speed search operation - select on indexed columns, downgrade insert, update, delete.

sql database sqlite database-design