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Purge or recreate a Ruby on Rails database
...test:prepare for testing, or else you'll get an error like: Could not find table 'things' (ActiveRecord::StatementInvalid)
– s2t2
Feb 17 '13 at 1:49
34
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What is best tool to compare two SQL Server databases (schema and data)? [duplicate]
I would like to compare two SQL Server databases including schema (table structure) and data in tables too. What is best tool to do this?
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Store boolean value in SQLite
What is the type for a BOOL value in SQLite? I want to store in my table TRUE/FALSE values.
8 Answers
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MySQL order by before group by
...hor is to use a subquery to return the max date and then join that to your table on both the post_author and the max date.
The solution should be:
SELECT p1.*
FROM wp_posts p1
INNER JOIN
(
SELECT max(post_date) MaxPostDate, post_author
FROM wp_posts
WHERE post_status='publish'
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How does grep run so fast?
...looks first
for the final letter of the target string, and uses a lookup table to
tell it how far ahead it can skip in the input whenever it finds a
non-matching character.
GNU grep also unrolls the inner loop of Boyer-Moore, and sets up the
Boyer-Moore delta table entries in such a way...
Make outer div be automatically the same height as its floating content
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I know some people will hate me, but I've found display:table-cell to help in this cases.
It is really cleaner.
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What is an ORM, how does it work, and how should I use one? [closed]
...(book);
}
With an ORM library, it would look like this:
book_list = BookTable.query(author="Linus");
The mechanical part is taken care of automatically via the ORM library.
Pros and Cons
Using ORM saves a lot of time because:
DRY: You write your data model in only one place, and it's easier...
Where are my postgres *.conf files?
... # analyze
#autovacuum_vacuum_scale_factor = 0.2 # fraction of table size before vacuum
#autovacuum_analyze_scale_factor = 0.1 # fraction of table size before analyze
#autovacuum_freeze_max_age = 200000000 # maximum XID age before forced vacuum
# (change requires re...
What is a columnar database?
...are build upon traditional, row-oriented, DBMS, simply storing the info in tables with one (or rather often two) columns (and adding the necessary layer to access the columnar data in an easy fashion).
How do they differ from relational databases?
They generally differ from traditional (row-oriente...
Calculating moving average
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In data.table 1.12.0 new frollmean function has been added to compute fast and exact rolling mean carefully handling NA, NaN and +Inf, -Inf values.
As there is no reproducible example in the question there is not much more to addres...