Topic: Philosophy about speed MySQL. Curiosity. Comparing. Development.
With MySQL I work only the third year. The main actions learned. Before worked 10 years with MDB (Access). There there are restrictions 2 on basis, 255 water a maximum in one table. But it is possible to learn easily through designers elements SQL.
Wanted to ask about speed.
Not clearly as interacts PHP with MySQL as a whole.
For example when I program and is remote through the driver "MySQK ODBC 5.2 Unicode Driver" I do request
SELECT * FROM Tbl
That if many table weighs, 5 seconds can be necessary even
And if to select only the necessary fields
SELECT p1, p2, p2 FROM Tbl
That process very fast.
The impression is made that the table single line, and at first all request (result) entirely is read not arrives to me in the buffer (theoretically judging by time) and then I read only a line. and in PHP as?
2. For this reason for me it is not clear why for example engine DLE broke the data on two tables POST and POST_EXTRAS (there there is nothing separate). In table POST_EXTRAS there are such additional fields as: editing date, an amount of reviews and others. Not really if these two tables to unite in one and to use request
UPDATE =+1 FROM POST WHERE id=1
This request unless will work more slowly if in the table many fields (if there a lot of the text information)?
Simply I will not understand what for then them disconnected then to waste time on connections to type JOIN which well precisely not will faster. Or in MySQL special magic in this respect?