Why are these indexes important in SQL?
It is likely that you also have an increasing amount of data over time, and with the increase in the existing data in the database, the speed of query execution may decrease. One of the useful tools for improving this performance is the use of these indexes. These indexes serve as a solution for quicker access to records of interest in the database table used and can significantly reduce the execution time of queries.
How do these indexes work?
These indexes act somewhat like libraries, with the difference that instead of finding a book, they help find the data records more efficiently. These indexes are usually built based on a column (or columns) from your table so that searching for records is performed as efficiently as possible.
Creating an index in SQL
To create an index, the CREATE INDEX command is commonly used. For example, if you want to create an index on the column customer_code from the table customers, you could use the following command:
CREATE INDEX idx_customer_code ON customers (customer_code);
Advantages and disadvantages of using these indexes
While these indexes can help increase the speed of searches, you must also consider that using these indexes can lead to increased disk space usage and longer times for updating and inserting data. Therefore, choosing the right columns that should be indexed is of great importance to the performance.
CREATE INDEX: This command is used to start creating a new index.
idx_customer_code: The name of the index that you can choose; this name is unique for this index in the database.
ON customers: The name of the table on which this index is created.
(customer_code): The column (or columns) that this index will be based on.