Home Database Mysql Tutorial What are the classifications of mysql indexes?

What are the classifications of mysql indexes?

Apr 22, 2024 pm 07:12 PM
mysql mysql index

MySQL indexes are divided into the following types: 1. Ordinary index: matching value, range or prefix; 2. Unique index: ensuring unique value; 3. Primary key index: unique index of the primary key column; 4. Foreign key index : Points to the primary key of another table; 5. Full-text index: full-text search; 6. Hash index: equal match search; 7. Spatial index: geospatial search; 8. Composite index: search based on multiple columns.

What are the classifications of mysql indexes?

MySQL Index Classification

Index is a structure in MySQL used to quickly find and retrieve data. They help reduce the time required to scan a data table by creating pointers to data in the table. There are the following types of indexes in MySQL:

1. Ordinary index (BTREE index)

  • The most common index type.
  • Can be used to match column value, range or prefix search.
  • Can have multiple columns.

2. Unique index

  • Ensure that the column value is unique in the table.
  • Can speed up finding records based on unique columns.
  • Can have multiple columns.

3. Primary key index

  • Special type of primary key, unique and non-empty.
  • MySQL automatically adds the table's primary key to the primary key index.

4. Foreign key index

  • An index pointing to the primary key of another table.
  • Can establish relationships between tables and enforce integrity constraints.

5. Full-text index (FTS index)

  • For full-text search on text and numeric fields.
  • Allows searching based on keywords or phrases.

6. Hash index

  • maps key values ​​directly to data pages.
  • Applies only to equal match searches.
  • Faster than BTREE index, but takes up more storage.

7. Spatial index

  • is used to index geospatial data.
  • Supports search based on location, range and distance.

8. Composite index

  • An index composed of multiple columns.
  • Can speed up searches based on multiple columns.
  • The order and order of each column is important.

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