To create main database applying three applications on various locations

Question

Hello all.

i am faced the issue on programming of my appliaction consider as :

i am intend to create the application to manage three shops on different locations using only database, but i don't know to use which method to apply this my application.

i am intend to create a main database to put at another location , and applications on diffiferent locations connect to main database and interact with them susch as : staffs can be check out,manage, delete and update the bills on the shop look as scan barcode,after that data will be update on main database.

I don't know which methods to apply this case as : web service ,remoting connection, or local database after the end of day we will collect all database on three locations to statistics.

Could you give me recommendation ?

Thanks and best regards

Sam Hobbs · Answer

Does the manufacturer of the device provide a sample program? There are many Windows programs written by others that use scanners like that; you should be able to find articles and samples. For most of those the developer has already gone through the process of solving unexpected problems. This is the type of thing that you need to expect unexpected problems. For example the TextChanged event fires each time a key is pressed. So it will fire 9 times when there are less than 10 digits and then when you have 10 digits your program will not know if that is all the data. Do you know if there is a carriage return (code 13) and/or a linefeed (code 10) at the end of the line? Does the device have a way to send any other text before and/or after the barcode?

benzema kirism · Answer

Hi Jean Paul In this form we don't use the click button Let consider the case if customers buys one hundred items that she/he will be click one hundred times. In this case  we are Automatic activation to execute add/insert to customer's bill on the TextChanged event. We can validate on the Textchanged event I don't know my direction is wrong or right now . i need you give me comment or suggestion Thanks and best regards

Jean Paul · Answer

Hi Kirism My opinion is that if you write the code in text change event then there arises manageability problem as - scanner changes text - user inputs text Better to write the validations on a button click event. You can check for empty range validations based on the Business Logic. Regards

benzema kirism · Answer

yes Thanks to Jean Paul and Sam Hobbs Now my application is using a USB barcode scanner that it is work as keyboard . i am intend to handle barcode change based on TextChanged event of Textbox and compare the string on the barcode that it should be have the length from 10 to 13  and do something here . and try to handle keyPress event when the staff enters somthing. Are there other events can be occurs in this case ? Please give me recommendation if it is possible ? Thanks and best regards

Sam Hobbs · Answer

There are many scanners that send the data by emulating a keyboard and sending the data as keys. That sounds simple but it can be complicated not simple for Windows windows. The main problem is that if the form is not the active form then the data does not go where it is supposed to. If the TextBox is not the active control then the data will likely go somewhere it is not supposed to. So it might appear simple but the details can cause the project to require more programming than initially expected.

Jean Paul · Answer

You do not needed to check continuously for barcode scanning. Depending on your scanner the methods differs: 1. Usually the Scanner company will be providing SDK and there will be Event on a new barcode scanned. You can write code in the event and check with your database. 2. If you are having a USB barcode scanner then a textbox will be fine. The scanner works as a keyboard.

benzema kirism · Answer

Thanks for the great information. i think that i will refer to the remote sql server firstly after that i will improve the application by other techniques. My application is intend using a laser barcode scanner I want the scanner to read the barcode and transfer the barcode no and compare to remote database to get the general information for staff to check out the bills after the bills print to customer and another bill will be create. i am using a USB scanner directly into a textbox but dont know how to do it Do i need to create thread to run check barcode nonstop ? Please give me the direction or example codes ? Thanks and Best regards

Sam Hobbs · Answer

As Jean Paul indicates it is possible for applications to access databases in other systems across the internet. You need to be careful about security if you do that. Another possibility is a Cloud. You can have the database in a Cloud such as Microsoft Azure and then all your systems would use the database in the Cloud.

Jean Paul · Answer

Hello Kirism If you have enough time and wanted to follow enterprise architecting standars: - Create a WCF service and all applicaions talk with this service Or You can use SQL Server to connect to the remote sql server. You can still use the connection string to point to this remote sql server. Local Database for each application increase uptime of application during network down times. But additional overheads of synchronizing is there. There is a Microsoft framework called Sync - I believe this is useful for synchronization. Apart from that there is SmartClient Software Factory with features like local storage. Regards