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Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.
Let's say I have the following data.table in R :
3 Answers
3
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Resizing UITableView to fit content
...ve a question in a UILabel and a multiple choice answers displayed in UITableView , each row showing a multiple choice. Questions and answers will vary, so I need this UITableView to be dynamic in height.
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How to disable scrolling in UITableView table when the content fits on the screen
I have a few (grouped style) tables in my iphone app (only on part of the screen and added with Interface Builder though, not subclassed from UITableViewController ) that 80% of the time are small and will fit on the screen. When the table fits on the screen, I'd like to disable scrolling, to ma...
Relational Database Design Patterns? [closed]
...elationships using a foreign key.
Many-to-Many relationships with a bridge table.
Optional one-to-one relationships managed with NULLs in the FK column.
Star-Schema: Dimension and Fact, OLAP design.
Fully normalized OLTP design.
Multiple indexed search columns in a dimension.
"Lookup table" that con...
Optimise PostgreSQL for fast testing
...s should always be followed; see the version policy.
Don'ts
Do NOT put a tablespace on a RAMdisk or other non-durable storage.
If you lose a tablespace the whole database may be damaged and hard to use without significant work. There's very little advantage to this compared to just using UNLOGGED...
Multiple columns index when using the declarative ORM extension of sqlalchemy
...just Column objects, index=True flag works normally:
class A(Base):
__tablename__ = 'table_A'
id = Column(Integer, primary_key=True)
a = Column(String(32), index=True)
b = Column(String(32), index=True)
if you'd like a composite index, again Table is present here as usual you just...
Auto increment primary key in SQL Server Management Studio 2012
How do I auto increment the primary key in a SQL Server database table, I've had a look through the forum but can't see how.
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With MySQL, how can I generate a column containing the record index in a table?
...itialization without requiring a separate SET command.
Test case:
CREATE TABLE league_girl (position int, username varchar(10), score int);
INSERT INTO league_girl VALUES (1, 'a', 10);
INSERT INTO league_girl VALUES (2, 'b', 25);
INSERT INTO league_girl VALUES (3, 'c', 75);
INSERT INTO league_girl...
What is the difference between the Data Mapper, Table Data Gateway (Gateway), Data Access Object (DA
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Your example terms; DataMapper, DAO, DataTableGateway and Repository, all have a similar purpose (when I use one, I expect to get back a Customer object), but different intent/meaning and resulting implementation.
A Repository "acts like a collection, except with m...
Postgres: INSERT if does not exist already
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There is one caveat/side effect. In a table with sequence column (serial or bigserial), even if no row is inserted the sequence is incremented at every insert attempt.
– Grzegorz Luczywo
Jul 2 '17 at 12:10
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