Too many keys specified; max 64 keys allowed - How to solve MySQL error: Too many keys specified, max 64 keys allowed

Too many keys specified; max 64 keys allowed - How to solve MySQL error: Too many keys specified, up to 64 keys allowed, specific code examples are required

In the process of using MySQL for database development and management, sometimes we will encounter some error messages. One of the common errors is "Too many keys specified; max 64 keys allowed" (Too many keys specified; max 64 keys allowed) ). This error usually occurs when creating a table and trying to specify too many keys or indexes. This article will show you how to solve this problem and give specific code examples.

First, let us first understand what keys and indexes are in MySQL. A key is a column or set of columns that uniquely identifies each row in a table. An index is a data structure used to improve query performance by sorting one or more columns to make queries faster. In MySQL, we can create unique keys, primary keys, full-text indexes, etc. for table columns.

When we create a table, if too many keys or indexes are specified, the above error message will appear. This is because MySQL has certain limits on the number of indexes per table, allowing up to 64 keys or indexes.

There are two ways to solve this problem:

1. Reduce the number of keys or indexes: carefully evaluate the needs of the table and delete unnecessary keys or indexes. For some infrequently used columns, you can consider whether you really need to create an index, or only create it when needed.
2. Merge keys or indexes into one index: If the columns of some keys or indexes overlap or are similar, and their query patterns are also similar, consider merging them into one index. In this way, the number of indexes can be reduced while improving query performance.

Here are some specific code examples to help you solve this problem:

1. Reduce the number of keys or indexes:

-- 删除不必要的键或索引
ALTER TABLE your_table DROP INDEX index_name;

-- 删除无用的全文索引
ALTER TABLE your_table DROP FULLTEXT index_name;

2. Merge keys or indexes into one index:

-- 合并多个列到一个索引中
ALTER TABLE your_table ADD INDEX index_name (column1, column2, column3);

-- 合并多个列到一组前缀索引中
ALTER TABLE your_table ADD INDEX index_name (column1(10), column2(10), column3(10));

Note: Before using the above code example, please make sure to replace "your_table" and "index_name" in the code with the table you actually use name and index name.

In short, when solving the MySQL error "Too many keys specified; max 64 keys allowed", we can solve it by reducing the number of keys or indexes, or merging keys or indexes into one index. Evaluate and select appropriate operations based on specific needs and query patterns. Also, make sure to use appropriate code examples to perform the appropriate actions to avoid raising other errors.

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