大约有 43,000 项符合查询结果（耗时：0.0370秒） [XML]
Can PostgreSQL index array columns?
...0}');
INSERT INTO "Test" VALUES ('{10, 20, 30}');
CREATE INDEX idx_test on "Test" USING GIN ("Column1");
-- To enforce index usage because we have only 2 records for this test...
SET enable_seqscan TO off;
EXPLAIN ANALYZE
SELECT * FROM "Test" WHERE "Column1" @> ARRAY[2...
Programmatically retrieve memory usage on iPhone
...icture of usage over-all.
#import <mach/mach.h>
// ...
void report_memory(void) {
struct task_basic_info info;
mach_msg_type_number_t size = TASK_BASIC_INFO_COUNT;
kern_return_t kerr = task_info(mach_task_self(),
TASK_BASIC_INFO,
...
Adding a new value to an existing ENUM Type
...he new type.
-- 1. rename the enum type you want to change
alter type some_enum_type rename to _some_enum_type;
-- 2. create new type
create type some_enum_type as enum ('old', 'values', 'and', 'new', 'ones');
-- 3. rename column(s) which uses our enum type
alter table some_table rename column some...
How to avoid “if” chains?
...the basic flow, e.g. instead of
if (ok)
{
DoSomething();
}
else
{
_log.Error("oops");
return;
}
... you'd use....
if (!ok)
{
_log.Error("oops");
return;
}
DoSomething(); //notice how this is already farther to the left than the example above
When there is a long series of ...
Return a value if no rows are found in Microsoft tSQL
... but ideally it should return multiple values. select case when count(QTIB_REQ_)<1 then 0 else QTIB_REQ_ end from qb_requisitions_all where QTIB_REQ_ IN ($Req_disabled_WA) and CLIENT___BENCH___NON_BILLABLE NOT IN ( 'Non Billable', 'Non-Billable', 'NonBillable', 'Bench', 'Bench - SC Cleared S...
When to use self over $this?
...on-static and static member variables:
<?php
class X {
private $non_static_member = 1;
private static $static_member = 2;
function __construct() {
echo $this->non_static_member . ' '
. self::$static_member;
}
}
new X();
?>
Here is an example of incorr...
Sending HTTP POST Request In Java
...alue(), "UTF-8"));
byte[] out = sj.toString().getBytes(StandardCharsets.UTF_8);
int length = out.length;
We can then attach our form contents to the http request with proper headers and send it.
http.setFixedLengthStreamingMode(length);
http.setRequestProperty("Content-Type", "application/x-www-f...
How to force ASP.NET Web API to always return JSON?
...otiator : IContentNegotiator
{
private readonly JsonMediaTypeFormatter _jsonFormatter;
public JsonContentNegotiator(JsonMediaTypeFormatter formatter)
{
_jsonFormatter = formatter;
}
public ContentNegotiationResult Negotiate(
Type type,
Http...
Should all Python classes extend object?
...;>> class Bar(object): pass
...
>>> type(Bar())
<class '__main__.Bar'>
Also the rules for multiple inheritance are different in ways that I won't even try to summarize here. All good documentation that I've seen about MI describes new-style classes.
Finally, old-style classe...
jQuery Ajax File Upload
...Data.append("file", this.file, this.getName());
formData.append("upload_file", true);
$.ajax({
type: "POST",
url: "script",
xhr: function () {
var myXhr = $.ajaxSettings.xhr();
if (myXhr.upload) {
myXhr.upload.addEventListener(...