Finally, the primary key constraint is a mixture of the unique constraint and the not null constraint meaning the no two rows can have the same values in their columns and that a column must have data.Data cleansing or data cleaning is the process of detecting and correcting (or removing) corrupt or inaccurate records from a record set, table, or database and refers to identifying incomplete, incorrect, inaccurate or irrelevant parts of the data and then replacing, modifying, or deleting the dirty or coarse data.The inconsistencies detected or removed may have been originally caused by user entry errors, by corruption in transmission or storage, or by different data dictionary definitions of similar entities in different stores.Data cleansing differs from data validation in that validation almost invariably means data is rejected from the system at entry and is performed at the time of entry, rather than on batches of data.Based on your objective, you have to decide what types of questions will give you the information you need.Each question type is unique and provides different types of data.Data cleansing may be performed interactively with data wrangling tools, or as batch processing through scripting.After cleansing, a data set should be consistent with other similar data sets in the system.
The entire effort is directed towards inquiry, and the questions are the elements that perform the actual interrogation.
When using SQL, data validation is the aspect of a database that keeps data consistent but is very stupid to use. The key factors in data integrity are constraints, referential integrity and the delete and update options.
The main types of constraints in SQL are check, unique, not null, and primary constraints.
NET MVC, controllers define action methods that usually have a one-to-one relationship with possible user interactions, such as clicking a link or submitting a form.
For example, when the user clicks a link, a request is routed to the designated controller, and the corresponding action method is called. Action filters are custom attributes that provide a declarative means to add pre-action and post-action behavior to controller action methods.