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SQLite table constraint - unique on multiple columns
...Some other title');
sqlite> .mode col
sqlite> .headers on
sqlite> select * from t1;
id a b
---------- ---------- ----------------
1 Alice Some other title
2 Bob Palindromic guy
3 Charles chucky cheese
sq...
Running multiple async tasks and waiting for them all to complete
...; sequence, Func<T, Task> action) {
return Task.WhenAll(sequence.Select(action));
}
Call it like this:
await sequence.ForEachAsync(item => item.SomethingAsync(blah));
Or with an async lambda:
await sequence.ForEachAsync(async item => {
var more = await GetMoreAsync(item);
...
Sockets: Discover port availability using Java
...ee = false;
}
return portFree;
}
EDIT: If all you're trying to do is select a free port then new ServerSocket(0) will find one for you.
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How to connect to SQL Server database from JavaScript in the browser?
...onnectionstring);
var rs = new ActiveXObject("ADODB.Recordset");
rs.Open("SELECT * FROM table", connection);
rs.MoveFirst
while(!rs.eof)
{
document.write(rs.fields(1));
rs.movenext;
}
rs.close;
connection.close;
A better way to connect to a sql server would be to use some server side lang...
C# DropDownList with a Dictionary as DataSource
...fy "Value" and "Key" for DataTextField and DataValueField respectively, to select the Value/Key properties.
Thanks to Joe's comment, I reread the question to get these the right way round. Normally I'd expect the "key" in the dictionary to be the text that's displayed, and the "value" to be the val...
SQL, Postgres OIDs, What are they and why are they useful?
...ned system column oid will no longer be invisible by default. Performing a SELECT * will now include this column. Note that this extra “surprise” column may break naïvely written SQL code.
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Image resizing client-side with JavaScript before upload to the server
...ed in a script tag)
You can use it as follows:
<input type="file" id="select">
<img id="preview">
<script>
document.getElementById('select').onchange = function(evt) {
ImageTools.resize(this.files[0], {
width: 320, // maximum width
height: 240 // maximum heigh...
内存优化总结:ptmalloc、tcmalloc和jemalloc - 操作系统(内核) - 清泛网 - ...
... 总共32个vcpu。 16个table，每个5M row。
OLTP_RO测试包含5个select查询：select_ranges, select_order_ranges, select_distinct_ranges, select_sum_ranges,
可以看到在多核心或者多线程的场景下， jemalloc和tcmalloc带来的tps增加非常明显。
参考资料
glibc...
How to navigate through the source code by parts in CamelCase (instead of whole words)?
...g and disabling the setting called "Honor "CamelHumps" words settings when selecting on double click".
– Paul Lammertsma
Jan 22 '15 at 13:14
9
...
Verify if a point is Land or Water in Google Maps
...ue&with_field_names=true
You have to register and supply your key and selected layer number. You can search all their repository of available layers. Most of the layers are only regional, but you can find global also, like the World Coastline:
When you select a layer, you click on the "Service...