YII2 MODEL获取表字段方式

Question

YII2中，MODEL获取表字段作为属性的方式是使用“SHOW FULL COLUMNS FROM TABLE”，而不是直接写在MODEL中。这样不时读数据库信息，这种额外开销感觉没必要，毕竟表结果不经常修改的。是基于什么原因使用这种方式呢？

    protected function loadTableSchema($name)
    {
        $table = new TableSchema;
        $this->resolveTableNames($table, $name);

        if ($this->findColumns($table)) {
            $this->findConstraints($table);

            return $table;
        } else {
            return null;
        }
    }

    protected function findColumns($table)
    {
        $sql = 'SHOW FULL COLUMNS FROM ' . $this->quoteTableName($table->fullName);
        try {
            $columns = $this->db->createCommand($sql)->queryAll();
        } 
        .........
    }

Answer 1

你可以在生产环境中使用字段缓存，配置 db.php

'enableSchemaCache' => true,

Answer 2

    'enableSchemaCache' => true,
    // Name of the cache component used to store schema information
    'schemaCache' => 'cache',
    // Duration of schema cache.
    'schemaCacheDuration' => 86400, // 24H it is in seconds