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.

_ wrote:

if there would be time itself understood

And these are your problems.