大约有 37,000 项符合查询结果（耗时：0.0255秒） [XML]
There can be only one auto column
...
My MySQL says "Incorrect table definition; there can be only one auto column and it must be defined as a key" So when I added primary key as below it started working:
CREATE TABLE book (
id INT AUTO_INCREMENT NOT NULL,
accepted_terms BIT(1) NO...
How to get all registered routes in Express?
...('/api/questions', questionsRoute);
I renamed the document.js file in apiTable.js and adapted it like this:
module.exports = function (baseUrl, routes) {
var Table = require('cli-table');
var table = new Table({ head: ["", "Path"] });
console.log('\nAPI for ' + baseUrl);
console....
MySql : Grant read only options?
...ns on database.
It depends on how you define "all read."
"Reading" from tables and views is the SELECT privilege. If that's what you mean by "all read" then yes:
GRANT SELECT ON *.* TO 'username'@'host_or_wildcard' IDENTIFIED BY 'password';
However, it sounds like you mean an ability to "see" ...
Can dplyr package be used for conditional mutating?
...for other better ways to handle the problem, here's another way using data.table:
require(data.table) ## 1.9.2+
setDT(df)
df[a %in% c(0,1,3,4) | c == 4, g := 3L]
df[a %in% c(2,5,7) | (a==1 & b==4), g := 2L]
Note the order of conditional statements is reversed to get g correctly. There's no co...
How to Delete using INNER JOIN with SQL Server?
...
You need to specify what table you are deleting from, here is a version with an alias:
DELETE w
FROM WorkRecord2 w
INNER JOIN Employee e
ON EmployeeRun=EmployeeNo
WHERE Company = '1' AND Date = '2013-05-06'
...
Difference between clustered and nonclustered index [duplicate]
I need to add proper index to my tables and need some help.
6 Answers
6
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How does database indexing work? [closed]
... N/2 block accesses (on average), where N is the number of blocks that the table spans. If that field is a non-key field (i.e. doesn’t contain unique entries) then the entire tablespace must be searched at N block accesses.
Whereas with a sorted field, a Binary Search may be used, which has log2 ...
Add timestamps to an existing table
I need to add timestamps ( created_at & updated_at ) to an existing table. I tried the following code but it didn't work.
...
How many concurrent AJAX (XmlHttpRequest) requests are allowed in popular browsers?
...cript">
var _settimer;
var _timer;
var _waiting;
$(function(){
clearTable();
$('#boton').bind('click', donow);
})
function donow(){
var w;
var estim = 0;
_waiting = $('#total')[0].value * 1;
clearTable();
for(var r=1;r<=_waiting;r++){
w = Math.floor(Math.random()*6)+2;
...
iOS 7: UITableView shows under status bar
The first screen of my application is a UITableViewController without a navigation bar, which means that the content flows under the status bar so there's a lot of text collisions. I've adjusted both the properties for Under top bars and Adjust scroll view insets which do actually stop it from...