Изисквания за съхранение на тип низ
| Data Type | Storage Required |
|---|---|
CHAR( |
The compact family of InnoDB row formats optimize storage for
variable-length character sets. See
COMPACT Row Format Storage Characteristics.
Otherwise, M ×
w bytes, <=
255, where
w is the number of bytes
required for the maximum-length character in the character
set. |
BINARY( |
M bytes, 0 <=
255 |
VARCHAR(,
VARBINARY( |
L + 1 bytes if column values require 0
− 255 bytes, L + 2 bytes
if values may require more than 255 bytes |
TINYBLOB,
TINYTEXT |
L + 1 bytes, where
L <
28 |
BLOB, TEXT |
L + 2 bytes, where
L <
216 |
MEDIUMBLOB,
MEDIUMTEXT |
L + 3 bytes, where
L <
224 |
LONGBLOB,
LONGTEXT |
L + 4 bytes, where
L <
232 |
ENUM(' |
1 or 2 bytes, depending on the number of enumeration values (65,535 values maximum) |
SET(' |
1, 2, 3, 4, or 8 bytes, depending on the number of set members (64 members maximum) |
Изисквания за съхранение на цифров тип
| Data Type | Storage Required |
|---|---|
TINYINT |
1 byte |
SMALLINT |
2 bytes |
MEDIUMINT |
3 bytes |
INT,
INTEGER |
4 bytes |
BIGINT |
8 bytes |
FLOAT( |
4 bytes if 0 <= p <= 24, 8 bytes if 25
<= p <= 53 |
FLOAT |
4 bytes |
DOUBLE [PRECISION],
REAL |
8 bytes |
DECIMAL(,
NUMERIC( |
Varies; see following discussion |
BIT( |
approximately (M+7)/8 bytes |
Leave a comment
No comments