大约有 2,000 项符合查询结果（耗时：0.0138秒） [XML]
Can Flask have optional URL parameters?
...
Another way is to write
@user.route('/<user_id>', defaults={'username': None})
@user.route('/<user_id>/<username>')
def show(user_id, username):
pass
But I guess that you want to write a single route and mark username as optional? If that's t...
Possible to do a MySQL foreign key to one of two possible tables?
...signate which target table is referenced.
CREATE TABLE popular_places (
user_id INT NOT NULL,
place_id INT NOT NULL,
place_type VARCHAR(10) -- either 'states' or 'countries'
-- foreign key is not possible
);
There's no way to model Polymorphic Associations using SQL constraints. A foreig...
generate model using user:references vs user_id:integer
... that this is the case:
:001 > Micropost
=> Micropost(id: integer, user_id: integer, created_at: datetime, updated_at: datetime)
The second command adds a belongs_to :user relationship in your Micropost model whereas the first does not. When this relationship is specified, ActiveRecord wi...
SQL query for finding records where count > 1
...have more than one payment per day with the same account number
SELECT
user_id ,
COUNT(*) count
FROM
PAYMENT
GROUP BY
account,
user_id ,
date
Having
COUNT(*) > 1
Update
If you want to only include those that have a distinct ZIP you can get a distinct set first and then perform you HAV...
What is the difference between a stored procedure and a view?
...hen and why to use each.
Say I have two tables:
tbl_user, with columns: user_id, user_name, user_pw
tbl_profile, with columns: profile_id, user_id, profile_description
So, if I find myself querying from those tables A LOT... instead of doing the join in EVERY piece of SQL, I would define a view...
How to implement a unique index on two columns in rails
...
add_index :subscriptions, [:user_id, :content_id], unique: true
share
|
improve this answer
|
follow
|
...
Rails has_and_belongs_to_many migration
...
You need to add a separate join table with only a restaurant_id and user_id (no primary key), in alphabetical order.
First run your migrations, then edit the generated migration file.
Rails 3
rails g migration create_restaurants_users_table
Rails 4:
rails g migration create_restaurants...
How to change the foreign key referential action? (behavior)
...e refers to Users table:
mysql> SHOW CREATE TABLE UserDetails;
:
:
`User_id` int(11) DEFAULT NULL,
PRIMARY KEY (`Detail_id`),
KEY `FK_User_id` (`User_id`),
CONSTRAINT `FK_User_id` FOREIGN KEY (`User_id`) REFERENCES `Users` (`User_id`)
:
:
First step:
mysql> ALTER TABLE `UserDeta...
Mail multipart/alternative vs multipart/mixed
...MessageInternal(service, "me", message1)
def SendMessageInternal(service, user_id, message):
try:
message = (service.users().messages().send(userId=user_id, body=message).execute())
print 'Message Id: %s' % message['id']
return message
except errors.HttpError, error:...
What is a proper naming convention for MySQL FKs?
...d table name]_[referencing field name]
Example:
CREATE TABLE users(
user_id int,
name varchar(100)
);
CREATE TABLE messages(
message_id int,
user_id int
);
ALTER TABLE messages ADD CONSTRAINT fk_messages_users_user_id
FOREIGN KEY (user_id) REFERENCES users(user_...