Is it OK to use varchar as primary key?
It is perfectly acceptable to use a varchar column as the primary key. This is often the case when one uses a natural key that doesn’t happen to be an integer.
Is there a real performance difference between int and varchar primary keys?
It’s not about performance. It’s about what makes a good primary key. Unique and unchanging over time. You may think an entity such as a country code never changes over time and would be a good candidate for a primary key.
Should a primary key be an integer?
A primary key can be any data type so long as the key/records(s) in question is/are unique. It is usually recommended to use integer primary keys as these are the fastest way to determine relations.
What field type would be the best for a integer based primary key?
Data Type. Integer (number) data types are the best choice for primary key, followed by fixed-length character data types. SQL Server processes number data type values faster than character data type values because it converts characters to ASCII equivalent values before processing, which is an extra step.
Should primary key always be a number?
The primary key should be numeric or date (avoid the use of text data types). The primary key should be compact (avoid the use of long data types). Shorter data types are faster to join than longer. The primary key should contain the fewest possible number of columns (limit the use of compound keys).
Can a primary key be a string in mysql?
2 Answers. The short answer : It’s perfectly fine to use a string as a primary key.
What is a natural primary key?
The primary. key is a unique value that identifies each record. Sometimes the primary key is. made up of real data and these are normally referred to as natural keys, while. other times the key is generated when a new record is inserted into a table.
Why an integer is better as a primary key?
Why Integers Make Good Primary Keys It’s often easier to use an integer for indexing, in comparison to a string or composite key, because it lends itself well to treating results (conceptually or in practice) as an array.
Is primary key always a number?
It is a unique identifier, such as a driver license number, telephone number (including area code), or vehicle identification number (VIN). A relational database must always have one and only one primary key.
What is the difference between varchar and integer?
Integer is for numbers, and varchar is for numbers, letters and other characters (Short text). So for age you can use a int type, for genders you can use the enum() type if there are only two options. Varchar is text and integer is number.
What are the two rules of primary key?
The general rules when designing a primary key are:
- The primary key value must uniquely identify one and only one record within the table.
- The primary key value must NOT be null.
- The primary key value must NOT change.