大约有 37,000 项符合查询结果（耗时：0.0389秒） [XML]
How to choose the id generation strategy when using JPA and Hibernate
...that are unique only when no other process is inserting data into the same table. Do not use in a cluster.
identity
supports identity columns in DB2, MySQL, MS SQL Server, Sybase and HypersonicSQL. The returned identifier is of type long, short or int.
sequence
uses a sequence in DB2, PostgreSQL, Or...
What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?
...h gives 31-lzcnt for non-zero inputs.)
There's unfortunately no way to portably take advantage of the various CLZ instructions on non-x86 platforms that do define the result for input=0 as 32 or 64 (according to the operand width). x86's lzcnt does that, too, while bsr produces a bit-index that th...
How can I select multiple columns from a subquery (in SQL Server) that should have one record (selec
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select t1.*, sq.*
from table1 t1,
(select a,b,c from table2 ...) sq
where ...
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When to use Hadoop, HBase, Hive and Pig?
.... It's a distributed, scalable, big data store, modelled after Google's BigTable. It stores data as key/value pairs.
Coming to Hive. It provides us data warehousing facilities on top of an existing Hadoop cluster. Along with that it provides an SQL like interface which makes your work easier, in ca...
How to make a select with array contains value clause in psql
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Try
SELECT * FROM table WHERE arr @> ARRAY['s']::varchar[]
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How to select only date from a DATETIME field in MySQL?
I have a table in the MySQL database that is set up with DATETIME . I need to SELECT in this table only by DATE and excluding the time.
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How to export and import a .sql file from command line with options? [duplicate]
...an we set constraints like enable/disable foreign key check or export only table structure with mysqldump
– AZinkey
Feb 28 '15 at 2:48
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What IDE to use for Python? [closed]
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On my smartphone browser, this table is completely unreadable.
– Axel
Nov 14 '14 at 7:53
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PostgreSQL: How to change PostgreSQL user password?
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The user is an object, not a string. Compare with ALTER TABLE "table_name" or even SELECT * FROM "table_name". You couldn't use single quotes in these contexts with tables, and it's the same with users/roles.
– P Daddy
Apr 13 '16 at 5:11
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How do you manage databases in development, test, and production?
...and have your CI server run those scripts on the database. Have a version table to keep track of the current database version, and only execute the scripts if they are for a newer version.
Use a migration solution. These solutions vary by language, but for .NET I use Migrator.NET. This allows you...