mysql 有没有map类型

CREATE TABLE example (
    id INT AUTO_INCREMENT PRIMARY KEY,
    data JSON
);

INSERT INTO example (data) VALUES ('{"name": "Alice", "age": 30}');
SELECT data->'$.name' AS name FROM example;

CREATE TABLE key_value_store (
    key VARCHAR(255) PRIMARY KEY,
    value TEXT
);

INSERT INTO key_value_store (key, value) VALUES ('name', 'Alice');
SELECT value FROM key_value_store WHERE key = 'name';

CREATE TABLE hash_table (
    key VARCHAR(255) PRIMARY KEY,
    value TEXT
) ENGINE=MEMORY;

INSERT INTO hash_table (key, value) VALUES ('name', 'Alice');
SELECT value FROM hash_table WHERE key = 'name';

ALTER TABLE example ADD COLUMN name VARCHAR(255);
UPDATE example SET name = JSON_UNQUOTE(JSON_EXTRACT(data, '$.name'));
CREATE INDEX idx_name ON example(name);