Question

方案：拥有超过十个表的数据库的Android应用程序。必须从服务器获取数据并将其存储到sq-lite（移动）数据库。为了有效地执行此操作，我计划计算每个表的行大小。具有为属性分配的长度。

 ----------------------------------------------------------------------------------
|  table_name             |  Size of single row with defined attributes length     |
|----------------------------------------------------------------------------------|
|  table_1                |                   size                                 |
|----------------------------------------------------------------------------------|
|  table_2                |                   size                                 |
|----------------------------------------------------------------------------------|
|  table_3                |                   size                                 |
 ----------------------------------------------------------------------------------

是否有任何mysql查询计算表格在创建时分配给属性的长度的单行长度？

就像我找到了显示表格大小的查询：

SELECT table_name AS "Table", 
round(((data_length + index_length) / 1024 / 1024), 2) "Size in MB" 
FROM information_schema.TABLES 
WHERE table_schema = "$DB_NAME"
 AND table_name = "$TABLE_NAME";

或此查询列出数据库中每个表的大小，最大的第一个：

SELECT table_name AS "Tables", 
round(((data_length + index_length) / 1024 / 1024), 2) "Size in MB" 
FROM information_schema.TABLES 
WHERE table_schema = "$DB_NAME"

ORDER BY (data_length + index_length) DESC;

Answer 1

我不相信你真的需要知道每一行的大小。您可以通过将表的大小除以记录总数来计算它们的平均值。

select count(*) into @tableRecordCount from table_name;

select table_name as "Tables".
round(((data_length + index_length) / (1024 * 1024 * @tableRecordCount), 2) "Size in MB per record"
from information_schema.TABLES
where table_schame = "$DB_NAME"
order by (data_length + index_length) desc;

使用mysql估计表大小

1 个答案: