大约有 374 项符合查询结果（耗时：0.0368秒） [XML]
中文网（自研/维护）拓展 · App Inventor 2 中文网
...程 IoT专题 AI2拓展 ChatGPT接入 Aia Store 开通VIP 搜索 中文网（自研/维护）拓展
中文网（自研/...
PDO Prepared Inserts multiple rows in single query
...like this, assuming a 3-column table you'd like to INSERT to.
INSERT INTO tbl_name
(colA, colB, colC)
VALUES (?, ?, ?), (?, ?, ?), (?, ?, ?) [,...]
ON DUPLICATE KEY UPDATE works as expected even with a multi-row INSERT; append this:
ON DUPLICATE KEY UPDATE colA = VALUES(colA), c...
App Inventor 2 低功耗蓝牙 BlueToothLE 拓展 · App Inventor 2 中文网
...程 IoT专题 AI2拓展 ChatGPT接入 Aia Store 开通VIP 搜索
App Inventor 2 低功耗蓝牙 BlueToothLE 拓展
...
How do we control web page caching, across all browsers?
...no-store, must-revalidate"); Response.AppendHeader("Expires", "Thu, 01 Dec 1994 16:00:00 GMT"); I figure, if it's good enough for them, it's good enough for me.
– John
Feb 12 '13 at 16:14
...
What does the brk() system call do?
...s://github.com/torvalds/linux/blob/v5.0/arch/x86/entry/syscalls/syscall_64.tbl#L23
12 common brk __x64_sys_brk
Is brk POSIX?
brk used to be POSIX, but it was removed in POSIX 2001, thus the need for _GNU_SOURCE to access the glibc wrapper.
The removal is likely due to the introduction...
Database, Table and Column Naming Conventions? [closed]
...s more good than harm. I worked in a db once where data tables began with tbl, config tables with ctbl, views with vew, proc's sp, and udf's fn, and a few others; it was meticulously, consistently applied so it worked out okay. The only time you NEED prefixes is when you have really separate solut...
Filter rows which contain a certain string
...
note that this does not work when the object is a tbl_sql as grepl does not translate to sql.
– David LeBauer
Aug 11 '15 at 17:17
...
How can I prevent SQL injection in PHP?
... queries.
($conn is a PDO object)
$stmt = $conn->prepare("INSERT INTO tbl VALUES(:id, :name)");
$stmt->bindValue(':id', $id);
$stmt->bindValue(':name', $name);
$stmt->execute();
share
|
...
What's the fastest way to merge/join data.frames in R?
...avy = mean(y))
and setup the data for dplyr with a data table:
dt <- tbl_dt(d)
dt_dt <- group_by(dt, g1, g2)
Updated: I removed data.tableBad and plyr and nothing but RStudio open (i7, 16GB ram).
With data.table 1.9 and dplyr with data frame:
test replications elapsed relati...
How to make a great R reproducible example
... dput is that it will not work for keyed data.table objects or for grouped tbl_df (class grouped_df) from dplyr. In these cases you can convert back to a regular data frame before sharing, dput(as.data.frame(my_data)).
Worst case scenario, you can give a text representation that can be read in usin...