Keys in the context of database have the following functions

When considered in a database management system, the term is, in fact, quite crucial. A key concept is vital to make data non-ambiguous; it helps expedite data searches or link tables in a database. This article provides an overview of the different types of keys and their importance with regards to why they are crucial to DB systems.

What is a Key

An index in a database means a field or one or several fields which are used to locate records within a table. In a relational database, keys play a vital role in arranging and retrieving data in a deterministic method if keys where not in place then the database system would be disorganized. Er Cues are markers which bind together components, related to each other, for the purpose of accurate and proper organization.

Types of Keys

1. Primary Key

A primary key is a field or a combination of fields which can distinguish only one record from the table. It also enables the condition where none of the rows in a table contain the same key value within the Primary key field and does not enable any null values. For instance, in the table of ‘employees,’ an “EmployeeID” field can be the candidate key.

2. Foreign Key

A foreign key creates a relationship with another table in which it references one or more columns in this other table. It is a field or a set columns in one table that points to a specific record in another table. Foreign keys keep the database properly linked so that a value placed in one table matches a value in the other table.

3. Candidate Key

A candidate key is an attribute or a set of attributes in which one record in a table can be made unique. Each table can have more than one candidate keys, although, only one of the keys can be adopted as the main entry key.

4. Composite Key

Composite means that two or more fields of the table are combined and provide a single means of record identification. This is often used where one field is not enough to serve a key field as distinct

 5. Unique Key

An example of constraint gives all values in a determined column of a table or in determined columns with the same key value or unique values. While it is similar to the primary key, the unique key can take a null field when it is allowable, however, only one null field per column.

6. Alternate Key

An alternate key is the one, which is not chosen in the pursuit of a primary key. These keys can also be used as backup unique identifiers of a table or structures.

Importance of Keys

1. Ensuring Data Integrity

Keys make certain that the data stored in a database is correct and if not, making it so. For example, primary keys eliminate data duplication whereas the foreign keys helps to maintain integrity of tables relationships.

2. Making data more accessible in order to enhance the speed of data access was another objective.

Indexes are formed when creating keys, during which primary and unique keys are generated to enhance the efficiency of data extraction procedures. This is important in the case of storing a large number of records and fast queries therefore should be important.

3. Establishing Relationships

In the relative database, the keys help determine the way in which tables are related. Keys such as the foreign keys in this case, results in creation of relations with the following intents; The ability to analyze and report meaningful information.

4. Understanding of Supporting Database Normalization

Normalization is the normalization of data to reduce the redundancy of data. Normalization is done by keys, especially in linking tables without repeated entries being created.

Best Practices for Using Keys

Choose Meaningful Keys: If possible, always use keys which have inherent meaning like the Social Security Numbers or ISBN numbers etc.

Avoid Changing Primary Keys: This is because changing a primary key will once again affect relations and may cause poor data integrity.

Use Surrogate Keys When Necessary: However, if you have natural keys that do not map well or are not a good idea, then an auto increment integer key is better.

Enforce Referential Integrity: It is good to always set the constraints to foreign keys this will ensure that all the relationships between the tables are consistent.

Conclusion

Any system of relations contains the most important part – keys. These are used to maintain the accuracy of data and also facilitate data search and the set table relationship. In general, keys according to Tripathi and Joshi are the most important tools in the construction of reliable and scalable databases. In any case, comprehending the concept of keys will undoubtedly be beneficial, especially if you are a DBA at any level of the learning curve.

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