From: Joaquín <javalpi@gmail.com>
I need query tables that are in two different databases
mysql_select_db("DB1", $conn_1);
mysql_select_db("DB2", $conn_2);
$result_t1 = mysql_query("SELECT * FROM Table1inDB1",$conn_1);
$row_t1 = mysql_fetch_assoc($result_t1);
$result_t2 = mysql_query("SELECT * FROM Table2inDB2",$conn_2);
$row_t2 = mysql_fetch_assoc($result_t2);
Although Joaquín said his issue is [Fixed], I write these queries as:
SELECT * FROM DB1.TableInDB1
SELECT * FROM DB2.TableInDB2
(with and without link_identifiers I believe), so I was wondering about best practices.
I can see if you already have code written without the DB in the FROM clause, it could be easier to have multiple links.
I haven't really used multiple links, but I ran into issues with multiple databases and consistently setting the correct DB, so now if I know I'll be using multiple DB's, I just write the query with the DB in the FROM clause. (A prior fix was to select the DB before each query. But if it was already selected, it seemed like a waste {according to my "by inspection" profiler}. So I started using the DB in the FROM clause.)
Are there any recommendations regarding best practices between:
1) using multiple links and table.field (or table) notation
versus
2) database.table.field (or database.table) notation?
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