Topic: Re: Creation of communications in mysql
First two tables true, short of absence of a key field which role, possibly, fulfills . The cipher. Add. And it is not clear, why the cipher is made varchar th.
I do not see the table of Teachers. Create.
The last table more or less - only FK on teachers it is somehow made without an index that hardly it turns out, and in primary key of the teacher under the job should not be. Plus I do not see FK on disciplines. And type usages numeric for the whole it is not justified, integer it will be more reasonable.
if there would be time itself understood
And these are your problems.