大约有 40,000 项符合查询结果（耗时：0.0396秒） [XML]
TransactionManagementError “You can't execute queries until the end of the 'atomic' block” while usi
...onTestCase, on the other hand, is perhaps misleadingly named: it truncates tables to reset the db -- the naming seems to reflect that you can test transactions within a test, not that the test is wrapped as a transaction!
– C S
Sep 20 '18 at 17:40
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How do SO_REUSEADDR and SO_REUSEPORT differ?
...dress. Depending on the destination address and the content of the routing table, the system will pick an appropriate source address and replace the "any" binding with a binding to the chosen source IP address.
By default, no two sockets can be bound to the same combination of source address and so...
How do you use script variables in psql?
...nd can then be substituted, for example, as ...
SELECT * FROM :myvariable.table1;
... or ...
SELECT * FROM table1 WHERE :myvariable IS NULL;
edit: As of psql 9.1, variables can be expanded in quotes as in:
\set myvariable value
SELECT * FROM table1 WHERE column1 = :'myvariable';
In olde...
How to become an OpenCart guru? [closed]
...n using
$result = $this->db->query("SELECT * FROM `" . DB_PREFIX . "table`");
DB_PREFIX as the name suggests is a constant containing the database prefix if one exists
$result will return an object for SELECT queries, containing a few properties
$result->row contains the first row's da...
Return rows in random order [duplicate]
Is it possible to write SQL query that returns table rows in random order every time the query run?
6 Answers
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How efficient is locking an unlocked mutex? What is the cost of a mutex?
... system limit. But too many of them spells nightmare for debugging. Simple table:
Less locks means more contentions (slow syscalls, CPU stalls) and lesser parallelism
Less locks means less problems debugging multi-threading problems.
More locks means less contentions and higher parallelism
More lo...
Is it safe to parse a /proc/ file?
...s even less consistent than that. It's atomic only within each row of the table. To see this, look at listening_get_next() in net/ipv4/tcp_ipv4.c and established_get_next() just below in the same file, and see the locks they take out on each entry in turn. I don't have repro code handy to demonst...
Can I create a named default constraint in an add column statement in SQL Server?
In SQL Server, I have a new column on a table:
4 Answers
4
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Trimming a huge (3.5 GB) csv file to read into R
...p://colbycol.r-forge.r-project.org/
It passes any arguments along to read.table, so the combination should let you subset pretty tightly.
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Is it correct to use DIV inside FORM?
...l. You can try it yourself at a HTML validator. Besides, it is almost inevitable these days, since the modern pages are build on div's. If it was not allowed, a simple wrapper or placing the form in a container would already make the page invalid.
– Nrzonline
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