[Derby]数据库操作说明

1. 创建新数据库

connect 'jdbc:derby:mydb;create=true';

ij> connect 'jdbc:derby:mydb;create=true';

ij>

将在当前目录下建立数据库目录 mydb;如果已经存在数据库 mydb,则提示：

警告 01J01：未创建数据库"mydb"，而是建立到现有数据库的连接。

ij> connect 'jdbc:derby:mydb;create=true';

警告 01J01：未创建数据库"mydb"，而是建立到现有数据库的连接。

ij>

2. 创建新表/删除表

create table mytable(number varchar(4), name varchar(10), age int, address varchar(40));

ij> create table mytable(number varchar(4), name varchar(10), age int, address varchar(40));

已插入／更新／删除 0 行

ij>

//删除整个表

drop table mytable;

ij> drop table mytable;

已插入／更新／删除 0 行

ij>

3. 表中添加数据

ij> insert into mytable values('1001', 'one', 20, 'street 1');

已插入／更新／删除 1 行

ij> insert into mytable values('1002', 'two', 22, 'street 2');

已插入／更新／删除 1 行

ij> select * from mytable;

NUM&|NAME |AGE |ADDRESS

--------------------------------------------------------------------

1001|one |20 |street 1

1002|two |22 |street 2

已选择 2 行

4. 查看表

show tables;

ij> show tables;

TABLE_SCHEM |TABLE_NAME |REMARKS

------------------------------------------------------------------------

SYS |SYSALIASES |

SYS |SYSCHECKS |

SYS |SYSCOLPERMS |

SYS |SYSCOLUMNS |

SYS |SYSCONGLOMERATES |

SYS |SYSCONSTRAINTS |

SYS |SYSDEPENDS |

SYS |SYSFILES |

SYS |SYSFOREIGNKEYS |

SYS |SYSKEYS |

SYS |SYSROUTINEPERMS |

SYS |SYSSCHEMAS |

SYS |SYSSTATEMENTS |

SYS |SYSSTATISTICS |

SYS |SYSTABLEPERMS |

SYS |SYSTABLES |

SYS |SYSTRIGGERS |

SYS |SYSVIEWS |

SYSIBM |SYSDUMMY1 |

APP |MYTABLE |

最后一个是我们自己创建的表 MYTABLE

5. 查看表的结构

describe mytable;

ij> describe mytable;

------------------------------------------------------------------------------

AGE |INTEGER |0 |10 |10 |NULL |NULL |YES

已选择 4 行

ij>

6. 表中添加数据

insert into mytable values('1001', 'one', 20, 'street 1');

insert into mytable values('1002', 'two', 22, 'street 2');

ij> insert into mytable values('1001', 'one', 20, 'street 1');

已插入／更新／删除 1 行

ij> insert into mytable values('1002', 'two', 22, 'street 2');

已插入／更新／删除 1 行

ij>

7. 查询数据

select * from mytable;

select number, name from mytable;

ij> select * from mytable;

NUM&|NAME |AGE |ADDRESS

--------------------------------------------------------------------

1001|one |20 |street 1

1002|two |22 |street 2

已选择 2 行

ij> select number, name from mytable;

NUM&|NAME

---------------

1001|one

1002|two

已选择 2 行

8. 更新数据

update mytable set name = 'one_one' where number = '1001';

ij> update mytable set name = 'one_one' where number = '1001';

已插入／更新／删除 1 行

ij> select * from mytable;

NUM&|NAME |AGE |ADDRESS

--------------------------------------------------------------------

1001|one_one |20 |street 1

1002|two |22 |street 2

已选择 2 行

ij>

9. 删除表中数据，保留表格式

delete from mytable where name = 'two';

delete from mytable;

ij> delete from mytable where name = 'two';

已插入／更新／删除 1 行

ij> select * from mytable;

NUM&|NAME |AGE |ADDRESS

--------------------------------------------------------------------

1001|one_one |20 |street 1

已选择 1 行

ij> delete from mytable;

已插入／更新／删除 1 行

ij> select * from mytable;

NUM&|NAME |AGE |ADDRESS

--------------------------------------------------------------------

已选择 0 行

ij> describe mytable;

------------------------------------------------------------------------------

AGE |INTEGER |0 |10 |10 |NULL |NULL |YES

已选择 4 行

ij>