(Transfer) Java data type and MySql data type corresponding table

java mysql data type comparison

type name	Display length	database type	JAVA type	JDBC type index (int)	describe
VARCHAR	L+N	VARCHAR	java.lang.String	12
CHAR	N	CHAR	java.lang.String	1
BLOB	L+N	BLOB	java.lang.byte []	-4
TEXT	65535	VARCHAR	java.lang.String	-1
INTEGER	4	INTEGER UNSIGNED	java.lang.Long	4
TINYINT	3	TINYINT UNSIGNED	java.lang.Integer	-6
SMALLINT	5	SMALLINT UNSIGNED	java.lang.Integer	5
MEDIUMINT	8	MEDIUMINT UNSIGNED	java.lang.Integer	4
BIT	1	BIT	java.lang.Boolean	-7
BIGINT	20	BIGINT UNSIGNED	java.math.BigInteger	-5
FLOAT	4+8	FLOAT	java.lang.Float	7
DOUBLE	22	DOUBLE	java.lang.Double	8
DECIMAL	11	DECIMAL	java.math.BigDecimal	3
BOOLEAN	1	同TINYINT
ID	11	PK (INTEGER UNSIGNED)	java.lang.Long	4
DATE	10	DATE	java.sql.Date	91
TIME	8	TIME	java.sql.Time	92
DATETIME	19	DATETIME	java.sql.Timestamp	93
TIMESTAMP	19	TIMESTAMP	java.sql.Timestamp	93
YEAR	4	YEAR	java.sql.Date	91

For bolb, it is generally used for database storage of pictures. The principle is to convert the pictures into binary, and then perform a storage method, which corresponds to the byte[] array in java.

For the boolen type, in the mysql database, I personally think that it is better to use the int type instead, and it is not very convenient for bit operations, especially in projects with web page development, which means 0/1, which corresponds to the java type Integer is better.

 

The declaration syntax for decimal columns is decimal(m,d).

在mysql5.1中，参数的取值范围： 
1、M是数字的最大数（精度）。其范围为1～65（在较旧的MySQL版本中，允许的范围是1～254）。 
2、D是小数点右侧数字的数目（标度）。其范围是0～30，但不得超过M。 
说明：float占4个字节，double占8个字节，decimail(M,D)占M+2个字节。 
如DECIMAL(5, 2) 的最大值为9 9 9 9 . 9 9，因为有7 个字节可用。 

 

 

 

REFS:http://www.cnblogs.com/jerrylz/p/5814460.html