PHP MySQL: The Data Type of FieldTag: mysql, database, field, data type Category: PHP Database
post: 28 Feb 2008 read: 1,382
php mysql basic step by step tutorial - part 4: There are some type of MySQL field data, such as:
Numeric data type
It differentiates into two kinds of group, there are integer and floating point data type.
For the most information of numeric data type, you just take a look at the table beneath:
| Data type |
Gyration assess |
| TINYINT |
(-128) - 127 or 0 - 255 |
| SMALLINT |
(-32768) - 32767 or 0 - 65535 |
| MEDIUMINT |
(-8388608) - 8388607 or 0 - 16777215 |
| INT |
(-2147683648) - 2147683647 or 0 - 4294967295 |
| BIGINT |
(-9223372036854775808) - 9223372036854775807
or 0 - 18446744073709551615 |
| FLOAT(X) |
(-3.402823466E+38) - (-1.175494351E-38), 0, and
1.175494351E-38 - 3.402823466E+38. |
| FLOAT |
The same as above |
| DOUBLE |
(-1.7976931348623157E+308) - (-2.2250738585072014E-308),
0, and 2.2250738585072014E-308 - 1.7976931348623157E+308 |
Those data type needs memory requirement as follows:
| Data type |
Memory requirement needs |
| TINYINT |
1 byte |
| SMALLINT |
2 bytes |
| MEDIUMINT |
3 bytes |
| INT |
4 bytes |
| INTEGER |
4 bytes |
| BIGINT |
8 bytes |
| FLOAT(X) |
4 ifX <=24 or 8 if 25 <=X <=53 |
| FLOAT |
4 bytes |
| DOUBLE |
8 bytes |
| DOUBLE PRECISION |
8 bytes |
| REAL |
8 bytes |
| DECIMAL(M,D) |
M+2 bytes if D>0, M+1 bytes if D=0(D+2, if M
|
| NUMERIC(M,D) |
M+2 bytes if D>0, M+1 bytes if D=0(D+2, if M
|
String data type
The types of data that is included into String data such as:
| Data type |
Gyration assess |
| CHAR |
1-255 character |
| VARCHAR |
1-255 character |
| TINYLOB, TINYTEXT |
1-255 character |
| BLOB, TEXT |
1-65535 character |
| MEDIUMLOB, MEDIUMTEXT |
1-16777215 character |
| LONGLOB, LONGTEXT |
1-4294967295 character |
| ENUM('element1','element2',...) |
Maximal 65535 character |
| SET('element1','element2',...) |
Maximal 64 element |
Those data type needs memory requirement as follows:
| Data type |
Memory requirement needs |
| CHAR(M) |
M bytes, 1 <=M <=255 |
| VARCHAR(M) |
L+1 bytes, L <=M and 1 <=M <=255 |
| TINYLOB, TINYTEXT |
L+1 bytes, L <2^8 |
| BLOB, TEXT |
L+2 bytes, L<2^16 |
| MEDIUMLOB, MEDIUMTEXT |
L+3 bytes, L<2^24 |
| LONGBLOB, LONGTEXT |
L+4 bytes, L<2^32 |
| ENUM('element1','element2',...) |
1 or 2 bytes, depend to the number of element |
| SET('element1','element2',...) |
1, 2, 3, 4 or 8 bytes, depend to the number of element |
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