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When to use a key/value store such as Redis instead/along side of a SQL database?
.... I did recently
for one gps tracking system which was previously built on mysql as a
database.
ADVANTAGE
Every time the tracker broadcast data I do not need to open mysql connection and store on it. We can save it on redis and later migrate
to mysql using some other process. This will avoid conc...
setting multiple column using one update
How to set multiple columns of a table using update query in mysql?
2 Answers
2
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How can I transform string to UTF-8 in C#?
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If you want to save any string to mysql database do this:->
Your database field structure i phpmyadmin [ or any other control panel] should set to utf8-gerneral-ci
2) you should change your string [Ex. textbox1.text] to byte, therefor
2-1) define byte[]...
How to change a nullable column to not nullable in a Rails migration?
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This worked for me. Using MySql locally. When pushed and ran app in Heroku (Postgres) it crapped on column that was not null when I was writing it a null - rightfully so. Only "change_column_null" would work could not use "change_column ... :null =>...
Does a foreign key automatically create an index?
... I'm just about positive that PostgreSQL creates an index. I'm pretty sure MySQL does. Making the index makes a ton of sense, but IT'T NOT REQUIRED. After all, why reference something if every time the DB goes to look it up it has to do a tablescan?
– MBCook
Ma...
Null vs. False vs. 0 in PHP
...or a data value that doesn't exist in the database or is unknown. See dev.mysql.com/doc/refman/5.0/en/working-with-null.html or en.wikipedia.org/wiki/Null_%28SQL%29.
– Eli
Dec 5 '12 at 3:39
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Getting the PublicKeyToken of .Net assemblies
...Pravat> ([system.reflection.assembly]::loadfile("C:\Program Files (x86)\MySQL\Connector NET 6.6.5\Assemblies\v4.0\MySql.Data.dll")).FullName
like
PS C:\Users\Pravat> ([system.reflection.assembly]::loadfile("dll full path")).FullName
and will appear like
MySql.Data, Version=6.6.5.0, Cu...
SQL - using alias in Group By
...OUP BY is executed before the SELECT clause.
There are exceptions though: MySQL and Postgres seem to have additional smartness that allows it.
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Cleanest way to build an SQL string in Java
...d MERGE. You can create SQL like this:
String sql1 = DSL.using(SQLDialect.MYSQL)
.select(A, B, C)
.from(MY_TABLE)
.where(A.equal(5))
.and(B.greaterThan(8))
.getSQL();
String sql2 = DSL.using(SQLDialect.MYSQL)
...
TCP 的那些事儿（下） - 更多技术 - 清泛网 - 专注C/C++及内核技术
...情况太糟糕，反应也很强烈。
sshthresh = cwnd /2
cwnd 重置为 1
进入慢启动过程
2）Fast Retransmit算法，也就是在收到3个duplicate ACK时就开启重传，而不用等到RTO超时。
TCP Tahoe的实现和RTO超时一样。
TCP Reno的...