To answer your question as to the same column name being in both tables, you have to fully qualify each column if their names are shared (actually, it's a good idea to fully qualify with the abbreviated name at this point).
So, if you had two tables, such as Student and Student_Grades, both which had a Student_ID column, you would qualify it as Student.Student_ID and Student_Grades.Student_ID.
The wikipedia article that I linked has a good example of JOINs and the qualified naming that you have to do (in their example, it's an employee and their department).
I have been asked to use ASP on UNIX and I have no idea what the limitations are. I have pages using ASP on NT with SQL7, is there an easy transition for my current pages to work on UNIX? Any help is much appreciated. THX (5 Replies)
I had a person ask me if a Sql database can be run with Unix? I don't know can this be done? They only have Sql dba's and no oracle dba but want to use a Unix box???? (1 Reply)
Help!
SCO Unix 5.05.
A relatievely new system went down on me today. I got the dreaded error:
Out of Space on Device (1/42).
I was able to clear up some space in the /tmp directory, however, when I try to boot, the system prompts me to go into single user mode and I get the... (2 Replies)
I want to check which databases are installed on my FreeBSD installation. This is what I did: pkg_info | grep mysql
How do I check all in one go whether also sqlite, postgresql, firebird is installed?
Thanks in advance (3 Replies)
Hi,
I'm the new user of mysql. I facing one problem to delete one of the database in mysql. Hope can get all of your suggestion and advice.
Input:
mysql> show databases;
+-------------------------+
| Database |
+-------------------------+
| information_schema |
|... (3 Replies)
I am facing problems with SVM installed on vmware workstation on intel platform. I have created replicas and a mirror volume using unmountable slices. But when I reboot my hardware I am not able to execute any SVM cmd's getting an error "there are no existing databases."
Below are o/p's of few... (0 Replies)
Hi Everyone,
I am new to DBA stuff. I wonder if anyone can help me. Task is that, I have 10 databases and need to take backups of all the databases using data pump in Unix/Linux, compress them using gzip and use cron to schedule the job twice a day.
Appreciate if anyone can help me in... (1 Reply)
Hello all again,
How do you guys backup your MySQL databases?
I have a few programs that have an default back up that make an .sql file which is great but I also use OpenX which runs on PHP and has a database. That does not have an auto-back-up feature so do I just download the... (2 Replies)
Discussion started by: AimyThomas
2 Replies
LEARN ABOUT REDHAT
symbol
Symbol(3pm) Perl Programmers Reference Guide Symbol(3pm)NAME
Symbol - manipulate Perl symbols and their names
SYNOPSIS
use Symbol;
$sym = gensym;
open($sym, "filename");
$_ = <$sym>;
# etc.
ungensym $sym; # no effect
# replace *FOO{IO} handle but not $FOO, %FOO, etc.
*FOO = geniosym;
print qualify("x"), "
"; # "Test::x"
print qualify("x", "FOO"), "
" # "FOO::x"
print qualify("BAR::x"), "
"; # "BAR::x"
print qualify("BAR::x", "FOO"), "
"; # "BAR::x"
print qualify("STDOUT", "FOO"), "
"; # "main::STDOUT" (global)
print qualify(*x), "
"; # returns *x
print qualify(*x, "FOO"), "
"; # returns *x
use strict refs;
print { qualify_to_ref $fh } "foo!
";
$ref = qualify_to_ref $name, $pkg;
use Symbol qw(delete_package);
delete_package('Foo::Bar');
print "deleted
" unless exists $Foo::{'Bar::'};
DESCRIPTION
"Symbol::gensym" creates an anonymous glob and returns a reference to it. Such a glob reference can be used as a file or directory handle.
For backward compatibility with older implementations that didn't support anonymous globs, "Symbol::ungensym" is also provided. But it
doesn't do anything.
"Symbol::geniosym" creates an anonymous IO handle. This can be assigned into an existing glob without affecting the non-IO portions of the
glob.
"Symbol::qualify" turns unqualified symbol names into qualified variable names (e.g. "myvar" -> "MyPackage::myvar"). If it is given a sec-
ond parameter, "qualify" uses it as the default package; otherwise, it uses the package of its caller. Regardless, global variable names
(e.g. "STDOUT", "ENV", "SIG") are always qualified with "main::".
Qualification applies only to symbol names (strings). References are left unchanged under the assumption that they are glob references,
which are qualified by their nature.
"Symbol::qualify_to_ref" is just like "Symbol::qualify" except that it returns a glob ref rather than a symbol name, so you can use the
result even if "use strict 'refs'" is in effect.
"Symbol::delete_package" wipes out a whole package namespace. Note this routine is not exported by default--you may want to import it
explicitly.
perl v5.8.0 2002-06-01 Symbol(3pm)