Ministry of Information Technologies and Communications of the Republic of Uzbekistan


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Ministry of Information Technologies and Communications of the Republic of Uzbekistan

Tashkent University of Information technologies named after Muhammad al-Kharazmi

Independent work


Subject: Database
Theme: Creating indexes in MySQL

Teacher: Abdul-Azalova Maxina


Student: Xolmonov Jonibek
Faculty: Economics and Management
Group:124-20 Ece

Tashkent 2021

PLAN:
1.Types of indexes in MySQL
2.Importance of indexes
3.Working with indexes in MySQL

1. What are indexes in MySQL


It is a tool that provides quick access to table rows based on the values of one and more columns. There is a lot of diversity in this operator because it is not standardized because the standards do not address performance issues. Index. The database object is a data structure, which consists of keys based on a table or varietal column of appearance and indicators that show the data based on one or more columns of the appearance. The indexes are designed to remove the lines faster than the table, in other words, the data in the prompt program gives significant improvements, which significantly improves the performance of applications and applications. The indexes can be used to ensure the specifics of the table strings and thus guarantee information integrity.
Microsoft SQL Server index types
Microsoft SQL Server is available in the following types of indices:
(Clustered) information table clustered index key value of the selected index. The table can be only one cluster index, since the data only in order to qualify. If possible, every table cluster index must be, if not a cluster index table, this table is called. "Heap". Cluster indexes are created automatically, PRIMARY KEY (primary key) and UNIQUE, if the table has not yet defined in the cluster index. When you create a cluster index table (adaptations), including indices, all of which are created, it needs to be reinstalled.
Key clusters (clusters), including the value of the index and the value of this key containing the data field. A cluster of several indices in the table. Cluster indexes, index or index tables can be created. It is these types of indices used to improve the performance of frequently used queries quickly, because the set of indices quick search and keys that provide access to information;
You can filter (filtered) for a set of rows in a table index is not optimized filter predicates using cluster index. Well, this type of index can improve query performance, as well as a complete index, indexes and reduce storage costs;
Unique (unique) to ensure there is a duplicate key (the same) with the values ​​of the index keys, as well as to guarantee the identity of these key clusters, and indexes in a single cluster. If you want to create multiple columns in a single index, the index value for each key combinations originality. PRIMARY KEY or UNIQUE limits, SQL Server automatically creates the key pillars of a single index. The unique index key columns in the table can be re-created only if there are no values;
Column index is based on the rule of stores (Column) technology. This type of index data warehouses, because it is effective for data storage as well as improve the performance of queries 10 times to 10 times the amount of data can be reduced, because Column store index data is compressed. There are also clustered columns, indexes, non-classified;
Full text search (full text) Character String complex effectively supported a special type of index. Full-text index and the process is referred to as "fill.". And the types of observations, such as filling to fill the filling. By default, SQL Server full-text index is created and then fill it completely, but it may require a large amount of resources, depending on the size of the table, so you can delay the plant. Track changes to the fill used to fill the full-text index.
Space (space) geometry or geography data type columns to allow the use of special operations more efficient index. This type of index can only spatial column in the structure and spatial index must be identified in the table as the primary key (primary key);
XML. XML data type for columns and other special type of index. XML index increases the efficiency of the processing of queries to XML columns. XML indexes are two types: primary and secondary. The main index of all stored in the XML column XML tags, values ​​and ways of indices. If the key to a table with a cluster index, you can create it. Secondary XML index only access to an XML index and the XML column in the table to improve the performance of certain types of queries that can be used to create secondary indexes for several types are available: PATH, VALUE and property;
Optimized memory tables indexes are (OLTP): Hash (Hashmi) indices, such as the memory and the range for the scanning and scanning the order of the cluster is not optimized for memory indices.


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