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How to pull a random record using Django's ORM?
... solutions with order_by('?')[:N] are extremely slow even for medium-sized tables if you use MySQL (don't know about other databases).
order_by('?')[:N] will be translated to SELECT ... FROM ... WHERE ... ORDER BY RAND() LIMIT N query.
It means that for every row in table the RAND() function will ...
How to get Top 5 records in SqLite?
...
SELECT * FROM Table_Name LIMIT 5;
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How to get a list of user accounts using the command line in MySQL?
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Use this query:
SELECT User FROM mysql.user;
Which will output a table like this:
+-------+
| User |
+-------+
| root |
+-------+
| user2 |
+-------+
As Matthew Scharley points out in the comments on this answer, you can group by the User column if you'd only like to see unique userna...
How to create a multi-tenant database with shared table structures?
..., it looks like the shared-database, single-schema approach is the most suitable. The fact that you'll be storing just about 50Mb per tenant, and that there will be no per-tenant add-ons, makes this approach even more appropriate.
The MSDN article cited above mentions three security patterns that t...
How to remove empty cells in UITableView? [duplicate]
i am trying to display a simple UITableView with some data. I wish to set the static height of the UITableView so that it doesn't displays empty cells at the end of the table. how do I do that?
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jsonify a SQLAlchemy result set in Flask [duplicate]
...# and what-not that aren't serializable.
d = dict()
for c in cls.__table__.columns:
v = getattr(inst, c.name)
if c.type in convert.keys() and v is not None:
try:
d[c.name] = convert[c.type](v)
except:
d[c.name] = "Error:...
How does a Java HashMap handle different objects with the same hash code?
...n, (it might be slightly different from Java 6).
Data structures
Hash table
Hash value is calculated via hash() on key, and it decide which bucket of the hashtable to use for a given key.
Linked list (singly)
When count of elements in a bucket is small, a singly linked list is used.
Red-Black t...
Create nice column output in python
...to set the columns to a minimum of 20 characters and align text to right.
table_data = [
['a', 'b', 'c'],
['aaaaaaaaaa', 'b', 'c'],
['a', 'bbbbbbbbbb', 'c']
]
for row in table_data:
print("{: >20} {: >20} {: >20}".format(*row))
Output:
a ...
MySQL select one column DISTINCT, with corresponding other columns
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try this query
SELECT ID, FirstName, LastName FROM table GROUP BY(FirstName)
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Child inside parent with min-height: 100% not inheriting height
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Second, the workaround I found:
If I set my container element to display:table with height:inherit it acts exactly the same way as if I'd give it a min-height of 100%. And - more importantly - if I set the child element to display:table-cell it will perfectly inherit the height of the container el...