大约有 43,000 项符合查询结果（耗时：0.0402秒） [XML]
Convert from enum ordinal to enum type
...diamonds and clubs! A C programmer would allocate 1 byte for each: 'const char CLUBS=0;' etc... Yes,a HashMap lookup is O(1), but the memory and CPU overhead of a HashMap, in this case make it many orders of magnitude slower and resource hungry than calling .values() directly! No wonder Java is suc...
Retrieving the text of the selected in element
...
function getSelectedText(elementId) {
var elt = document.getElementById(elementId);
if (elt.selectedIndex == -1)
return null;
return elt.options[elt.selectedIndex].text;
}
var text = getSelectedText('test');
...
INSERT INTO…SELECT for all MySQL columns
... manual. Try this:
INSERT INTO this_table_archive (col1, col2, ..., coln)
SELECT col1, col2, ..., coln
FROM this_table
WHERE entry_date < '2011-01-01 00:00:00';
If the id columns is an auto-increment column and you already have some data in both tables then in some cases you may want to omit t...
SQL DROP TABLE foreign key constraint
...your table, you could use this SQL (if you're on SQL Server 2005 and up):
SELECT *
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('Student')
and if there are any, with this statement here, you could create SQL statements to actually drop those FK relations:
SELECT
'ALTER TABL...
Html List tag not working in android textview. what can i do?
...
Instead of using the pasted bullet character, it may be better to use the unicode character: output.append("\n\t\u2022");
– Matt McMinn
Mar 10 '13 at 17:14
...
Change limit for “Mysql Row size too large”
...rows of your
tables plus the length of other variable length fields (VARCHAR, VARBINARY, and TEXT type fields).
In my situation the offending blob table was around 16MB. Thus, the way I solved it was by adding a line to my.cnf that ensured I had at least 10x that amount and then some:
innodb_l...
How do I safely pass objects, especially STL objects, to and from a DLL?
...ply specific packing. The compiler will still apply default packing if you select a pack value bigger than the one the compiler would have chosen, so if you pick a large packing value, a class can still have different packing between compilers. The solution for this is to use #pragma pack(1), which ...
MySQL Error 1215: Cannot add foreign key constraint
...
It could also be that the character set is different. I hade this problem where one column had the utf8 character set while the other had latin1. Easily fixed with ALTER TABLE Table CHARACTER SET = utf8 ; and ALTER TABLE Device CHANGE COLUMN ID ID CHA...
Query to count the number of tables I have in MySQL
...
SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'dbName';
Source
This is mine:
USE databasename;
SHOW TABLES;
SELECT FOUND_ROWS();
...
Difference between natural join and inner join
...+----------+
The INNER JOIN of TableA and TableB on Column1 will return
SELECT * FROM TableA AS a INNER JOIN TableB AS b USING (Column1);
SELECT * FROM TableA AS a INNER JOIN TableB AS b ON a.Column1 = b.Column1;
+------------+-----------+---------------------+
| a.Column1 | a.Column2 | ...