大约有 37,000 项符合查询结果（耗时：0.0361秒） [XML]
belongs_to through associations
...ter off caching the question_id on Choice and adding a unique index to the table (especially because validates_uniqueness_of is prone to race conditions).
If you're paranoid, add a custom validation to Choice that confirms that the answer's question_id matches, but it sounds like the end user shoul...
Why use the INCLUDE clause when creating an index?
...nd that get used a lot), it can be very helpful to INCLUDE those into a suitable non-clustered index.
share
|
improve this answer
|
follow
|
...
json_encode is returning NULL?
...
few day ago I have the SAME problem with 1 table.
Firstly try:
echo json_encode($rows);
echo json_last_error(); // returns 5 ?
If last line returns 5, problem is with your data. I know, your tables are in UTF-8, but not entered data. For example the input was i...
TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes
...set-unicode-utf8.html, max 3 bytes for utf-8.
THIS IS A ROUGH ESTIMATION TABLE FOR QUICK DECISIONS!
So the worst case assumptions (3 bytes per utf-8 char) to best case (1 byte per utf-8 char)
Assuming the english language has an average of 4.5 letters per word
x is the number of bytes allocated
...
How do I view the list of functions a Linux shared library is exporting?
...at must be loaded from other shared objects have a U. Note that the symbol table does not include just functions, but exported variables as well.
See the nm manual page for more information.
share
|
...
How do I center floated elements?
...g floats is easy. Just use the style for container:
.pagination{ display: table; margin: 0 auto; }
change the margin for floating elements:
.pagination a{ margin: 0 2px; }
or
.pagination a{ margin-left: 3px; }
.pagination a.first{ margin-left: 0; }
and leave the rest as it is.
It's the be...
What is a simple command line program or script to backup SQL server databases?
...tructure to access MSSQL databases. Here's a simple shell script to dump a table to a file:
#!/usr/bin/ksh
#
#.....
(
tsql -S {database} -U {user} -P {password} <<EOF
select * from {table}
go
quit
EOF
) >{output_file.dump}
...
PostgreSQL delete with inner join
...
for larger tables, the first solution in this answer is potentially much faster.
– mgoldwasser
Nov 2 '14 at 16:58
2
...
Simulate low network connectivity for Android [closed]
...
Set network latency emulation to . Default value is none. See
the table in Network Delay Emulation for supported values.
-netspeed <speed>
Set network speed emulation to . Default value is full. See
the table in Network Speed Emulation for supported values.
Speeds for re...
Remove the cell highlight color of UITableView
I want to remove the default blue color of uitableview cell selection. I don't want any selection color there. I have not created a custom cell class. I'm customizing the cell by adding labels and buttons over it.
I tried doing:
...