大约有 6,200 项符合查询结果（耗时：0.0159秒） [XML]
Is it a good idea to index datetime field in mysql?
.... In my application I will have many rows for example I currently have one table with 4 million records. Most of my queries use datetime clause to select data. Is it a good idea to index datetime fields in mysql database?
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ERROR: permission denied for sequence cities_id_seq using Postgres
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Interesting. I did a GRANT all on the table that my sequence is in, but this doesn't seem to cover the sequence. This also seems to very by OS.
– Kinnard Hockenhull
Jun 7 '14 at 15:48
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Should try…catch go inside or outside a loop?
...ch structures are placed. Internally, they are implemented as a code-range table in a structure that is created when the method is called. While the method is executing, the try/catch structures are completely out of the picture unless a throw occurs, then the location of the error is compared again...
SQL Server Profiler - How to filter trace to only display events from one database?
...lumn and find out the correct values to enter by querying the sysdatabases table in the master database
– Jim Birchall
Nov 10 '08 at 8:39
35
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MAC addresses in JavaScript
...ince any server-side programming language allows you do get access the ARP table, even indirectly (e.g. through a subprocess). I think "client-side language" would work better...
– kirbyfan64sos
Oct 6 '16 at 19:51
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How to use Oracle ORDER BY and ROWNUM correctly?
...ory, in Oracle, you need to limit the results manually when you have large tables and/or tables with same column names (and you don't want to explicit type them all out and rename them all). Easy solution is to figure out your breakpoint and limit that in your query. Or you could also do this in the...
What Java ORM do you prefer, and why? [closed]
..._ID = a.ID);
And how it can be expressed in jOOQ:
// Alias the author table
TAuthor a = T_AUTHOR.as("a");
// Use the aliased table in the select statement
create.selectFrom(a)
.whereExists(create.selectOne()
.from(T_BOOK)
.whe...
Performing user authentication in Java EE / JSF using j_security_check
...thenticate users based on username and MD5-hashed passwords in my database table:
http://blog.gamatam.com/2009/11/jdbc-realm-setup-with-glassfish-v3.html
Note: the post talks about a user and a group table in the database. I had a User class with a UserType enum attribute mapped via javax.persiste...
Omit rows containing specific column of NA
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It is possible to use na.omit for data.table:
na.omit(data, cols = c("x", "z"))
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Extracting hours from a DateTime (SQL Server 2005)
...dd(hour,12,time_received)
else time_received
END
from table
works
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