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What is “overhead”?
...uably more absurd) approach would be to post all of the inputs to some SQL table in an RDBMS. Then simply calling the SQL SUM function on that column of that table. This shifts our local memory overhead to some other server, and incurs network overhead and external dependencies on our execution. ...
How to convert timestamp to datetime in MySQL?
...
You can use
select from_unixtime(1300464000,"%Y-%m-%d %h %i %s") from table;
For in details description about
from_unixtime()
unix_timestamp()
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Python Sets vs Lists
... due to near instant 'contains' checks: https://en.wikipedia.org/wiki/Hash_table
List implementation: usually an array, low level close to the metal good for iteration and random access by element index.
Set implementation: https://en.wikipedia.org/wiki/Hash_table, it does not iterate on a list, but...
Generate full SQL script from EF 5 Code First Migrations
... Does this create an exact copy of the database? Including the table contents?
– Multitut
Mar 20 '15 at 14:36
2
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How to check for Is not Null And Is not Empty string in SQL server?
...ause. As NULL will evaluate as UNKNOWN for these rather than TRUE.
CREATE TABLE T
(
C VARCHAR(10)
);
INSERT INTO T
VALUES ('A'),
(''),
(' '),
(NULL);
SELECT *
FROM T
WHERE C <> ''
Returns just the single row A. I.e. The row...
An efficient way to transpose a file in Bash
... interestingly it prints out a directory listing for the first line of the table. I don't know enough BASH to figure out why.
– bugloaf
Jun 19 '13 at 19:50
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Map enum in JPA with fixed values?
...t option (this is a basic implementation, tweak it as required):
@Entity
@Table(name = "AUTHORITY_")
public class Authority implements Serializable {
public enum Right {
READ(100), WRITE(200), EDITOR (300);
private int value;
Right(int value) { this.value = value; } ...
What does “hashable” mean in Python?
... data structures use the hash value internally.
All of Python’s immutable built-in objects are hashable, while no mutable containers (such as lists or dictionaries) are. Objects which are instances of user-defined classes are hashable by default; they all compare unequal, and their hash value...
Career day in kindergarten: how to demonstrate programming in 20 minutes? [closed]
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I've done this before.
I laid down a lot of paper towels on a table, and got out a loaf of (cheap) bread, a small tub of butter, a small jar of jelly, and a plastic butter knife.
I said to the kids, "How many of you think computers are smart?" Most of them raised their hands. I said,...
Why should you use an ORM? [closed]
...
Making data access more abstract and portable. ORM implementation classes know how to write vendor-specific SQL, so you don't have to.
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