Shulou(Shulou.com)06/01 Report--

In this issue, the editor will bring you about what attributes can speed up the query operation. The article is rich in content and analyzes and describes for you from a professional point of view. I hope you can get something after reading this article.

The attribute that can speed up the query operation is "index". The index can be used to speed up the query and sorting of data. The index file is stored as a separate file, which contains pointers to table records. After the index is established, the physical order of the records in the table remains the same.

The attribute that can speed up query operations is Index.

The index can be used to speed up the query and sorting of the data. The index file is stored as an independent file, which contains pointers to the table records. After the index is established, the physical order of the records in the table remains unchanged.

Related introduction:

In a 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 list of logical pointers to a collection of one or more column values in a table and the corresponding 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.

These are the attributes that the editor shares to speed up the query operation. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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