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MySQL Great Circle Distance (Haversine formula)
...latitude in degrees',
`lon` FLOAT NOT NULL COMMENT 'longitude in degrees',
INDEX `lat_lon_idx` (`lat`, `lon`)
)
If you're using TokuDB, you'll get even better performance if you add clustering
indexes on either of the predicates, for example, like this:
alter table Coordinates add clustering ...
When to use MyISAM and InnoDB? [duplicate]
...s much less costs of server resources. -- Mostly no longer true.
Full-text indexing. -- InnoDB has it now
Especially good for read-intensive (select) tables. -- Mostly no longer true.
Disk footprint is 2x-3x less than InnoDB's. -- As of Version 5.7, this is perhaps the only real advantage of MyISA...
Physical vs. logical / soft delete of database record?
...siness needs.
EDIT: Thought of another disadvantange - If you have unique indexes on the table, deleted records will still take up the "one" record, so you have to code around that possibility too (for example, a User table that has a unique index on username; A deleted record would still block the...
efficient circular buffer?
...nderstandable when the deque can grow to infinity, but if maxlen is given, indexing an element should be constant time.
– lvella
Nov 13 '15 at 21:57
1
...
Creating range in JavaScript - strange syntax
...arr);
Number(i, arr);
Which returns the transformation of i, the current index, to a number.
In conclusion,
The expression
Array.apply(null, { length: 5 }).map(Number.call, Number);
Works in two parts:
var arr = Array.apply(null, { length: 5 }); //1
arr.map(Number.call, Number); //2
The fi...
How to read a text file into a string variable and strip newlines?
...
@J.C can you explain the problem ? Is this just a question of custom or does the with ... as statement bring something ?
– Titou
May 5 '17 at 12:08
4
...
Deleting DataFrame row in Pandas based on column value
...df[df.columns[2].notnull()], but one way or another you need to be able to index the column somehow.
– erekalper
Nov 9 '18 at 20:35
1
...
Replacing instances of a character in a string
...ou can do the below, to replace any char with a respective char at a given index, if you wish not to use .replace()
word = 'python'
index = 4
char = 'i'
word = word[:index] + char + word[index + 1:]
print word
o/p: pythin
...
AngularJS For Loop with Numbers & Ranges
...this. It should be a new attribute that works with two values. The current index and the upper bound.
– Ian Warburton
May 19 '13 at 18:49
10
...
Computed / calculated / virtual / derived columns in PostgreSQL
...e to list it explicitly.
Can also be supported with a matching expression index - provided the function is IMMUTABLE. Like:
CREATE FUNCTION col(tbl) ... AS ... -- your computed expression here
CREATE INDEX ON tbl(col(tbl));
Alternatives
Alternatively, you can implement similar functionality wi...