- How to connect database in vb net 2010 how to#
- How to connect database in vb net 2010 code#
- How to connect database in vb net 2010 password#
- How to connect database in vb net 2010 plus#
How to connect database in vb net 2010 code#
Overall review of the code sample below other than what is not mentioned above, the code to interact with a database is in the form, any code which reads and writes to the database should be in classes and called from the form. Uses named parameters but by default are done in ordinal positioning like MS-Access. WHERE ID=? AND Country = ? in the query create the parameters in the same order as MS-Access parameters are in ordinal position unlike SQL-Server where parameters are “named” parameters and for the record Oracle In the exact same order as in the field list e.g. For MS-Access, for each parameter you have a matching command parameter Using named parameters as shown in Button2 click event is how the WHERE condition should be constructed. There is) an exception will be thrown from the database and caught in the catch. Have meaningful names so when there are many button, TextBox etc controls while in code a developer may known what a button does by it’s name.Ĭardinal sin: Never append a concatenated WHERE condition to any query without using command parameters as done in Button1 click event to find a record, if there is a last name with an apostrophe in the field (and The developer copied code from the form load event and appended a WHERE condition in Button1 click event (all controls like buttons should
How to connect database in vb net 2010 plus#
The preferred event is the form’s Shown event plus having logic in the catch to deal with exceptions which should disallow the application to function normally plus alert the developer of issues using email or prompting the user to report the problem. Couple this with using form load event which is known to allow exceptions to be thrown and not reporting these exceptions while There is a try-catch statement with no logic in the catch which means any errors will go unnoticed. The table name from each field name, if there was a JOIN then each table in the JOIN may be aliased which will be shown later. In this case the command text can be improved by removing The SQL SELECT statement is in a string variable with the table name preceding field names, this usually happens when a developer writes the query in the database and paste the statement into their code. Since this is a read operation using a DataSet is overkill as only a DataTable is needed to read in data while depending on the application’s purpose may use a lighter weight container to populate the DataGridView control. cause orphan records and code to throw exceptions because If someone comes along that find this application not doing what they want that user can circumvent your application and open the database, make changes and very possibly cause issues in your program e.g.
How to connect database in vb net 2010 password#
The second issue is there are several places were the same connection string is duplicated and lastly, the database is not protected with a password which may or may not be needed yet in many cases Creating a dynamic connection will be shown later on.
![how to connect database in vb net 2010 how to connect database in vb net 2010](https://i.stack.imgur.com/Fqjg4.png)
The connection string is hard coded which means to deploy the application to another computer the path needs to be dynamic rather than hardĬode. In the code sample below, data is read from the database in the load event of the form. In this case the developer is novice level with the intent to start off by reading from an employee table and display the data intoĪ DataGridView control with an option to find an employee by last name. The following will lay the background to moving towards writing better code to access a database. Description Novice level reading and searching See the database design section below for ideas.
![how to connect database in vb net 2010 how to connect database in vb net 2010](https://i.stack.imgur.com/X5A8E.jpg)
Up struggling with a bad database design.
How to connect database in vb net 2010 how to#
Without problems that come from writing code without a clear understanding of how to interact with a Microsoft Access (MS-Access) database.īefore a Visual Studio solution is created first work out the database design, test the database to ensure all business requirements are met so that there is a clear path to follow rather than writing code and along the way end In this code sample/article methods which are also best practices will be introduced with the intent to allow a developer to write data centric applications Working with Microsoft Access database is relatively easy when a developer understands options to interact with a database and has a decent understanding of writing code yet these easy methods that seemingly work can quickly causeĪ developer to encounter problems on every turn of developing a data centric solution for their task.