Coders4Fun

I searched a way to do a daily backup of my wordpress blog in my home pc but I didn’t find nothing that completely satisfy me, so I decided to code it.
I separated the problem in two scripts:
The first, that is written in php and runs on the web server, makes the dump of mysql databases from my hosting provider and leaves the dump on the web server.
The other one (written in bash, and running locally) downloads the site and the mysql dump from the web server, via FTP. Unfortunately I discovered that my hosting provider (Aruba.it) didn’t supply with mysqldump its server.

First of all, I searched for a php script that makes the direct dump of the database.

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If we want to insert a date in a SQL string in C#, the solution seems obvious:

DateTime date = DateTime.Now;
string sql = "INSERT INTO tableWithDate VALUES(1, "+ date.ToString() + ")";

Unfortunately this code can’t work! The function DateTime.ToString() returns a string like 23/02/2007 19.00.49, while MySQL wants a string like 2007-02-23 19:00:49. The following static function converts a DateTime object in a valid date field for MySQL:

public static string GetSQLDate(DateTime date)
{
	string sql;
	sql = date.Year.ToString() + "-" + date.Month.ToString() + "-" + date.Day.ToString() + " "
	+ date.Hour.ToString() + ":" + date.Minute.ToString() + ":" + date.Second.ToString();
	return sql;
} 

I inserted the method in a utility class, that i called Utils, so the working code is:

string sql = "INSERT INTO tableWithDate VALUES(1, "+ Utils.GetSQLDate(date) + ")";

A deprecated method is a method that is no more supported. For example, you wrote an API with a function that saves something on the disk but in the future versions of your program you want to support only Database saves. In this case you can deprecate the method that saves to disk for a lot of versions: the programmers are now warned from the compiler every time they use the function, and have the time to migrate the code.

If you want to deprecate a method in c#, you can simply add the Obsolete attribute in the function.

[Obsolete("This is a deprecated method.")]
public void DeprecatedMethod()
{
	MessageBox.Show(”I’m a deprevated method! XD”);
}

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Today at work i had my daily dilemma: how can i save a blob field in a MySQL DB with c#??? The solution it’s pretty simple, but it can be hard to find.

The Blob is a binary field where data can be saved: the problem is that we must write these binary data in a textual SQL string. To resolve this problem we can convert the binary data in an hexadecimal representation in order to write the data in a textual format.

The resulting SQL will look like that:

INSERT INTO tableWithBlob VALUES(1,0xab425fa52d3e13);

Where 0x… are our binary data.

To start, we must first convert the data structure that we want to put in the database in a byte array (byte[]), or in a format in which we can access all structure’s bytes.
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Starting from the article “C++ timer”, we created a simply class that act as a wrapper to the Windows API and that easily allows to start a timer, stop it. and assign the function to call when the timer is elapsed.

The following is a little example that explains how to use the class:
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Stored Procedures are a way to re-use and parametrize long SQL queries.
To create a Stored Procedure you need at least MySql 5.0. Using MySQL Query Browser the stored procedure creation is very quick:

Right click on the database where do you want to create the procedure (from version 5.0.1 procedures are assigned to a specific database, instead in the 5.0 version the procedures are globals)

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