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Editor to share with you what the access index means, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

In access relational database, an index is a separate, physical storage structure that sorts the values of one or more columns in a database table. It is a collection of one or more column values in a table and a list of logical pointers that point to the data pages that physically identify these values in the table. The function of the index is equivalent to the catalogue of the book, and the content you need can be found quickly according to the page number in the catalog.

The index provides pointers to the data values stored in the specified column of the table, and then sorts those pointers according to the sort order you specify. The database uses an index to find a specific value, and then follows the pointer to the row that contains the value. This allows faster execution of SQL statements corresponding to tables and quick access to specific information in database tables.

When there are a large number of records in the table, if you want to query the table, the first way to search for information is a full table search, which takes out all the records one by one, compares them with the query conditions, and then returns the records that meet the conditions. This will consume a lot of database system time and result in a large number of disk I / O operations. The second is to establish an index in the table, then find the index value that meets the query criteria in the index, and finally quickly find the corresponding record in the table through the ROWID (equivalent to the page number) stored in the index.

The above is all the contents of the article "what does the access Index mean?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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