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Is it required that postgresql is installed on every client computers when retriveing or storing data?

I need your help to answer a question.
I coded a basic c# portable exe application that uses an Access Database on a server computer. On the network there are some client computers that runs this application and retrieve and store data via this database placed on the server computer in a shared folder. Every client coputer can access my database with this connection string:
#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source =\\ANKFILESERVER1\aractakip\DatabaseAd.accdb
So far, there has been no problem. But as known, Access (Oledb) database has a limited capacity to save datas and since i'm worrying that someone change or delete my database files -authenticated for everyone- i decieded to use another database platform like postgresql.
My question is, if i install postgresql on the server computer and migrate my database tables, Are every client computers needed to install postgresql to access my database tables? If yes, what should be my connection string?
Thanks in advance.

You will need a client driver - like psqlODBC - installed on each computer that connects to PostgreSQL via MS Access, yes.
You can install psqlODBC separately, or using the main PostgreSQL installer. The separate psqlODBC-only installer is an msi that can be deployed over Active Directory, making management easier.
The connection options are covered in the psqlODBC documentation.
Microsoft Access is really written for the Microsoft JET / OLEDB engine, and to communicate with Microsoft SQL Server. It works with PostgreSQL, but it doesn't fully "understand" all PostgreSQL's features. It also does some things in totally non-SQL-standard ways that work on MS SQL but do not work on PostgreSQL. So it can be awkward to use MS Access with PostgreSQL due to things like Access not really supporting SEQUENCEs properly. Note, though, that I haven't used Access since Office 2008, so things may have improved.

Good options for a MySQL Lighter version

I have a C#.NET application which connects to a MySQL database in a server.
I have a requirement to do some operations offline.( When the client machine does not have internet and cannot access the MySQL database.) My Plan is to create a MySQL database in local machine. Copy all files required to the local database and perform required operations. When the client machine have the access to the MySQL sever copy back the changed files to the server database.
My question is what are the good Options to use as local MySQL. Is there any lighter version of MySQL available?
I also need to install selected MySQL version with the windows installation package generated for my software.
Thanks in Advance.

When I have these situations I usually fall back to SqlLight. Its a simple embeddable database, and if you are using only the simplest insert /select statements you should not need to maintain much difference between your local database access vs the remote database access.
That said. If you are using something that is not that simple it's usually a good advice to bite the bullet and do the whole mySql install thing on the local machine. Because the maintenance of 2 sets of database access will eat up development time like nothing else.

In your case I would use an embedded database with your offline application, something like FireBird where you don't need to install a 3rd party database etc. The FireBird dll's are linked and part of your application deployment. http://www.firebirdsql.org/

Oracle: Cannot connect from entity framework

I've an oracle server, already installed on a remote server.
I've installed oracle latest provider, to use them in visual studio with entity framework.
But when I'm trying to connect to the server, I got this exception:
ORA-12560: TNS:protocol adapter error.
I'm really new to the oracle world, and I cannot find what is the problem or even how to debug it.
I saw that listeners are ups, by doing a lsnrctl status I've my listener on the port 1521.
But, I saw that i've the security like this: "Security ON: Local OS Authentication", but since I've no common users between the server and the client, can it make somes troubles?
Should I have some specials rights on my user? In local, I can connect myself with the sqldeveloper tools.
Any help would be greatly appreciated
EDIT
Some more informations:
The server runs under windows, it has the OracleXETNSListener service started. I forgot to mention, but the server firewall is off.
Edit 2
I tried to download the oracle sql developer on my workstation, and I connected myself with exactly the same informations.(I just saw that in fact sql developer use a "base" connection instead of "TNS", which seems to be used by the EF?

I ended by using the devart connector: http://www.devart.com/dotconnect/oracle/
it worked for me directly in all mode(Direct or normal). If only I did tried it this morning, I will have loosed less time.

Are you using your tns names via AD or locally on your machine? If it's local then you'll need to make sure that you have the correct connection descriptors listed in the tns names file located in the default location - this depends on Oracle version.
There are known issues around entity framework and connecting to remote instances, but these can be overcome with a l

Using the Oracle Provider, your connection string should look something like this:
Data Source={serverAddress}/xe;User Id={UserName};Password={Password};
Example:
Data Source=localhost/xe;User Id=scott;Password=tiger
I suggest you to always mention the Oracle Instance Identifier (which in the Express Edition is always xe), so you don't have to rely on your tns config settings.

C# application using SQL Server database

This might sound a silly question but I've really spend hours in trying to find a solution...
I have a local database on SQL Server and it is used with a C# application.. The only way I view the database is through SQL Server.. It is accessible and altered in my application when I am running the application on my developing PC, but when I run it on another PC the database is not found (obviously) .. How can I include the database sources when I am compiling the program, (so that it would be also found when I run it on other PCs) ?
Initially I used SQL Server CE and I achieved portability, but I had to include stored procedures, and this edition doesn't accept them :/ so I had to turn my attention to the latter type.
Sorry for my terrible English ! :(
Thanks in advance

How can I include the database sources when I am compiling the program, (so that it would be also found when I run it on other PCs) ?
You can't. SQL Server license prohibits distributing parts of it like that, plus there is no documented way to do that. If you need SQL Server on the box, it needs to come from the installer. You can create an installer for your own product, and your installer can install SQL Server if it's needed as a prerequisite.
Alternatively, you could look at other database options such as SQLite for a file-based database. You can distribute the components of SQLite.

If you need a local sql server on each pc where your application runs then you should look into the Express edition of MS SQL Server. It is the free with limitations version of MS SQL Server.

connecting remote mysql database using c#.net

I am developing c# windows application.
In that I want to connect to mysql database which resides in another system.
Please help me to solve this?

Assuming that you know how to connect to and query a database, you'll need the following:
The ADO.NET provider for MySQL
The hostname or IP address of the server
A user ID and password to connect with
Add a reference to the MySQL provider. From there, it works just like connecting to a SQL Server box, except the class names are a bit different and some minor SQL dialect is also different.
Of course, if you don't already know how to connect to a database, you'll need to start a bit slower. I'd recommend you Google yourself a basic data-access tutorial.
Good luck!