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SQLite add Primary Key
...Sqlite by using the CREATE TABLE AS syntax to create a table based on a SELECT statement. Now this table has no primary key but I would like to add one.
...
Is having an 'OR' in an INNER JOIN condition a bad idea?
... a MERGE JOIN.
It can be expressed as a concatenation of two resultsets:
SELECT *
FROM maintable m
JOIN othertable o
ON o.parentId = m.id
UNION
SELECT *
FROM maintable m
JOIN othertable o
ON o.id = m.parentId
, each of them being an equijoin, however, SQL Server's optimiz...
What does Redis do when it runs out of memory?
...s reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPU...
Is there an easy way to attach source in Eclipse?
...
Go to Properties (for the Project) -> Java Build Path -> Libraries
Select the Library you want to attach source/javadoc for and then expand it, you'll see a list like so:
Source Attachment: (none)
Javadoc location: (none)
Native library location: (none)
Access rules: (No restrictions)
Sel...
开源MQTT网关：EMQX vs Mosquitto - 创客硬件开发 - 清泛IT社区，为创新赋能！
引言物联网开发者需要为自己的物联网项目选择合适的 MQTT 消息产品或服务，从而构建可靠高效的基础数据层，保障上层物联网业务。目前市面上有很多开源的 MQTT 产品，在性能功能等方面各有优点。本文将选取目前最为流行的...
Select Row number in postgres
How to select row number in postgres.
1 Answer
1
...
How to conditionally push an item in an observable array?
...the following ($parent is due to this being inside a table row loop):
<select data-bind="visible: editing, hasfocus: editing, options: $parent.jobroles, optionsText: 'name', optionsValue: 'id', value: jobroleId, optionsCaption: '-- Select --'">
</select>
<...
How do I detect “shift+enter” and generate a new line in Textarea?
...tarea, in characters, from the start?
function getCaret(el) {
if (el.selectionStart) {
return el.selectionStart;
} else if (document.selection) {
el.focus();
var r = document.selection.createRange();
if (r == null) {
return 0;
}
...
Edit a commit message in SourceTree Windows (already pushed to remote)
...most recent commit) using SourceTree for Windows version 1.5.2.0:
Step 1
Select the commit immediately before the commit that you want to edit.
For example, if I want to edit the commit with message "FOOBAR!" then I need
to select the commit that comes right before it:
Step 2
Right-click on th...
Long-lasting FB access-token for server to pull FB page info
...page admin)
Head over to the Facebook Graph API Explorer
On the top right, select the FB App you created from the "Application" drop down list
Click "Get Access Token"
Make sure you add the manage_pages permission
Convert this short-lived access token into a long-lived one by making this Graph API c...