| ========================= | |
| Join promotion in the ORM | |
| ========================= | |
| [NOTE: We need better terms than promote and demote for changing the join | |
| type. These terms are extremely easy to mix up. Maybe the ORM methods could | |
| be to_inner_joins and to_louter_joins instead of promote_joins and demote_joins? | |
| I tried to clean up the mis-usages of promotion/demotion but there could still | |
| be some cases where these are mixed up] |
| group: bank example | |
| description[[ the data for this dataset was generated using <http://www.generatedata.com/> | |
| * the relation _Customers_ contains basic information about the customers of the bank. | |
| * the relation _Accounts_ contains the basic information of a single account. Note that a customer can have any number of accounts. | |
| * the relation _PremiumCustomers_ contains the customer-ids of all customers with a total balance over 1000 | |
| ]] | |
| Customers = { cid firstname lastname |
Good article also here: http://pankrat.github.io/2015/django-migrations-without-downtimes/
The following instructions describe a set of processes allowing you to run Django database migrations against a production database without having to bring the web service down.
Note that in the below instructions, migrations are all run manually at explicit points, and are not an automatic part of the deployment process.
| class Node: | |
| def __init__(self, value, key=None, next=None, prev=None): | |
| self.value = value | |
| self.next = next | |
| self.prev = prev | |
| self.key = key | |
| class LRUCache: |
| package main | |
| func gen(f int) chan int { | |
| // Creating non-buffered channel | |
| c := make(chan int) | |
| go func() { | |
| for i := 0; i < f; i++ { | |
| // This part of the code will be blocked until someone will read from c channel. | |
| c <- i |
