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What is the best way to use a HashMap in C++?
...rdered map insert and access is in O(1). It is just another name for a hashtable.
An example with (ordered) std::map:
#include <map>
#include <iostream>
#include <cassert>
int main(int argc, char **argv)
{
std::map<std::string, int> m;
m["hello"] = 23;
// check if ke...
PostgreSQL - max number of parameters in “IN” clause?
... possible if the inputs are all scalars (no RowExprs) and there is a
* suitable array type available. If not, we fall back to a boolean
* condition tree with multiple copies of the lefthand expression.
* Also, any IN-list items that contain Vars are handled as separate
* boolean conditions, bec...
Why can't a text column have a default value in MySQL?
If you try to create a TEXT column on a table, and give it a default value in MySQL, you get an error (on Windows at least). I cannot see any reason why a text column should not have a default value. No explanation is given by the MySQL documentation. It seems illogical to me (and somewhat frustrati...
Bulk insert with SQLAlchemy ORM
...scoped_session(sessionmaker())
engine = None
class Customer(Base):
__tablename__ = "customer"
id = Column(Integer, primary_key=True)
name = Column(String(255))
def init_sqlalchemy(dbname='sqlite:///sqlalchemy.db'):
global engine
engine = create_engine(dbname, echo=False)
...
Select row with most recent date per user
I have a table ("lms_attendance") of users' check-in and out times that looks like this:
11 Answers
...
Can I bind an array to an IN() condition?
...'));
$db = new PDO(...);
$stmt = $db->prepare(
'SELECT *
FROM table
WHERE id IN(' . $inQuery . ')'
);
// bindvalue is 1-indexed, so $k+1
foreach ($ids as $k => $id)
$stmt->bindValue(($k+1), $id);
$stmt->execute();
?>
fix: dan, you were right. fixed the code (did...
How to show multiline text in a table cell
I want to show a paragraph from database into a table cell.
10 Answers
10
...
What does android:layout_weight mean?
...specify a size ratio between multiple views. E.g. you have a MapView and a table which should show some additional information to the map. The map should use 3/4 of the screen and table should use 1/4 of the screen. Then you will set the layout_weight of the map to 3 and the layout_weight of the tab...
Quickly find whether a value is present in a C array?
... i, j, k, ... as needed, with left or right shifts)
Then you make a fixed table of n entries, where the hash maps the input values to an index i into the table. For valid values, table entry i contains the valid value. For all other table entries, ensure that each entry of index i contains some oth...
MySQL indexes - what are the best practices?
...going on.
Broadly speaking, an index imposes an ordering on the rows of a table.
For simplicity's sake, imagine a table is just a big CSV file. Whenever a row is inserted, it's inserted at the end. So the "natural" ordering of the table is just the order in which rows were inserted.
Imagine y...