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Naming convention for unique constraint
...imary key doesn't get a sequence number since there can be only one. The 2-char alpha suffix meanings are:
PK: Primary Key
AK: Alternate Key
FK: Foreign Key
IX: IndeX
CK: ChecK
DF: DeFault
I generally want to group metadata/system catalog data by the controlling object rather than by object type...
Filtering for empty or NULL names in a queryset
...null, not-empty alias field. The generated SQL would look something like:
SELECT * FROM Name WHERE alias IS NOT NULL AND alias != ""
You can also pass multiple arguments to a single call to exclude, which would ensure that only objects that meet every condition get excluded:
Name.objects.exclude...
How to Create Multiple Where Clause Query Using Laravel Eloquent?
...;orWhere($orThose)
->get();
The above will result in such query:
SELECT * FROM users
WHERE (field = value AND another_field = another_value AND ...)
OR (yet_another_field = yet_another_value AND ...)
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How to find out client ID of component for ajax update/render? Cannot find component with expression
... <ui:repeat>.
When using PrimeFaces, consider Search Expressions or Selectors
PrimeFaces Search Expressions allows you to reference components via JSF component tree search expressions. JSF has several builtin:
@this: current component
@form: parent UIForm
@all: entire document
@none: noth...
Legality of COW std::string implementation in C++11
...be seen in the following if COW were allowed: std::string a("something"); char& c1 = a[0]; std::string b(a); char& c2 = a[1]; c1 is a reference to a. You then "copy" a. Then, when you attempt to take the reference the second time, it has to make a copy to get a non-const reference since...
How to pull a random record using Django's ORM?
...on't know about other databases).
order_by('?')[:N] will be translated to SELECT ... FROM ... WHERE ... ORDER BY RAND() LIMIT N query.
It means that for every row in table the RAND() function will be executed, then the whole table will be sorted according to value of this function and then first N...
Meaning of $? (dollar question mark) in shell scripts
...k() == 0) {
/* Call false. */
execl("./false", "./false", (char *)NULL);
}
int status;
/* Wait for a child to finish. */
wait(&status);
/* Status encodes multiple fields,
* we need WEXITSTATUS to get the exit status:
* http://stackoverflow.com/questi...
How to find encoding of a file via script on Linux?
...ill output MIME-type information for the file, which will also include the character-set encoding. I found a man-page for it, too :)
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Why would you use an ivar?
..., @"Isabella", @"Ava",
@"Mia", @"Emily", @"Abigail", @"Madison", @"Charlotte"
];
const NSUInteger nameCount = maleNames.count;
assert(maleNames.count == femaleNames.count); // Better be safe than sorry
allAcocuntsA = [NSMutableArray arrayWithCapacity:ammount];
allAccount...
Get list of all tables in Oracle?
...
SELECT owner, table_name
FROM dba_tables
This is assuming that you have access to the DBA_TABLES data dictionary view. If you do not have those privileges but need them, you can request that the DBA explicitly grants you...