What are the types of indexes in SQL?
There are two types of Indexes in SQL Server:
- Clustered Index.
- Non-Clustered Index.
What types of data are good candidates for indexes?
Indexes are best suited to columns with a data type that can be given some meaningful order, ie sorted (integer, date etc).
Why indexes are used in SQL?
A SQL index is used to retrieve data from a database very fast. Indexing a table or view is, without a doubt, one of the best ways to improve the performance of queries and applications. A SQL index is a quick lookup table for finding records users need to search frequently.
What is the function of index in SQL?
What is the candidate key in SQL Server?
Candidate key is also called natural key, domain key, or business key. This key is unique. It may not necessarily be primary but it usually is. Primary key is unique and non-null. Employee SSN here is a candidate key. Business-wise it is natural to think that SSN will not be duplicated.
What to consider when indexing a SQL Server table?
In this case, you can create a large number of SQL Server indexes, adding all required columns as index key or non-key columns to enhance the performance of the SELECT queries and get the requested data faster. Another thing to consider when indexing a database table is the size of the table.
Is the GUID column a good candidate for indexing?
A GUID column is not the best candidate for indexing. Indexes are best suited to columns with a data type that can be given some meaningful order, ie sorted (integer, date etc). It does not matter if the data in a column is generally increasing.
What does the CREATE INDEX statement do in SQL?
Creating an index involves the CREATE INDEX statement, which allows you to name the index, to specify the table and which column or columns to index, and to indicate whether the index is in an ascending or descending order.