Data integrity in SQL refers to the overall accuracy, completeness, and consistency of data. It is maintained by a collection of processes, rules, and standards implemented during the design phase. When the integrity of data is secure, the information stored in a database will remain complete, accurate, and reliable, no matter how long it’s stored or how often it’s accessed.
In SQL databases, data integrity refers to ensuring that each row of a table is uniquely identified so that data can be retrieved separately. To achieve this, constraints on columns are used. Data constraints prevent invalid data entry into the base tables of the database, which helps maintain data integrity.
Entity integrity is one type of data constraint that ensures each row in a table is a uniquely identifiable entity. We can apply entity integrity to the table by specifying a primary key, a unique key, and not null. Other types of data integrity include domain integrity, which requires that a set of data conforms to a specific domain, and referential integrity, which ensures that relationships between tables remain consistent.
Data integrity is crucial for businesses because it is a necessary constituent of data integration. If data integrity is maintained, data values stored within the database are consistent about the data model and type, and reliable insights can then be gained from the data model so users can make informed business decisions.
