关于数据库字段自定义的问题求救

[wcarry21]

请大家帮忙
1、 增加、删除、修改（从小到大）数据库字段
2、 能修改字段名称、大小、数据类型
oracle数据库
谢谢

[liujun_cn]

请详细说明。

[liujun_cn]

请详细说明你的问题。

[wolfsquare]

如果不要求保留数据，这些很容易用SQL语句做到的。

[yanchang]

如果数据哭里已经有数据，
删除、数据库字段
能修改字段名称、大小、数据类型就麻烦了

看来是要自己开发个工具了

[zfluo]

alter_specification:
ADD [COLUMN] create_definition [FIRST | AFTER column_name ]
or ADD INDEX [index_name] (index_col_name,...)
or ADD PRIMARY KEY (index_col_name,...)
or ADD UNIQUE [index_name] (index_col_name,...)
or ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT}
or CHANGE [COLUMN] old_col_name create_definition
or MODIFY [COLUMN] create_definition
or DROP [COLUMN] col_name
or DROP PRIMARY KEY
or DROP INDEX key_name
or RENAME [AS] new_tbl_name
or table_option

[zfluo]

ALTER [IGNORE] TABLE tbl_name alter_spec [, alter_spec ...]

alter_specification:
ADD [COLUMN] create_definition [FIRST | AFTER column_name ]
or ADD INDEX [index_name] (index_col_name,...)
or ADD PRIMARY KEY (index_col_name,...)
or ADD UNIQUE [index_name] (index_col_name,...)
or ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT}
or CHANGE [COLUMN] old_col_name create_definition
or MODIFY [COLUMN] create_definition
or DROP [COLUMN] col_name
or DROP PRIMARY KEY
or DROP INDEX key_name
or RENAME [AS] new_tbl_name
or table_option

[zfluo]

ALTER [IGNORE] TABLE tbl_name alter_spec [, alter_spec ...]

alter_specification:
ADD [COLUMN] create_definition [FIRST | AFTER column_name ]
or ADD INDEX [index_name] (index_col_name,...)
or ADD PRIMARY KEY (index_col_name,...)
or ADD UNIQUE [index_name] (index_col_name,...)
or ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT}
or CHANGE [COLUMN] old_col_name create_definition
or MODIFY [COLUMN] create_definition
or DROP [COLUMN] col_name
or DROP PRIMARY KEY
or DROP INDEX key_name
or RENAME [AS] new_tbl_name
or table_option