1.创建一个新的表a，表结构及数据与emp一致.
create table a as select * from emp;
2 增加主键约束
alter table a add constraint pk_a_01 primary key(EMPNO);
3.为a增加一个字段birthdate,类型date。
alter table a add...
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数据库 时间：
2015-04-07 21:39:31
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210
You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security system connected and it will automatical...
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其他好文 时间：
2015-04-07 17:50:17
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147
House Robber
You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is t...
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其他好文 时间：
2015-04-07 15:43:40
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340
建表： create table 表名（字段名1 字段类型（长度） 约束,......）; 约束类型： 主键：（1）primary key （2）constraint 表名_字段名_pk priamry key(字段名) 不为空：（1） not null （2）constra...
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数据库 时间：
2015-04-07 11:48:06
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177
You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping yo...
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其他好文 时间：
2015-04-06 21:31:16
阅读次数：
131
You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping yo...
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其他好文 时间：
2015-04-06 16:59:50
阅读次数：
325
You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping yo...
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其他好文 时间：
2015-04-06 06:23:24
阅读次数：
148
题目： You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stoppin...
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其他好文 时间：
2015-04-06 06:13:15
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124
1，自动布局是一种基于约束的布局(constraint-based layout)引擎，它可以根据开发者在对象上的约束自动调整大小与位置。2.在iOS 6之前使用的布局模型是“spring&struts”模型。虽然大部分情况下运行很有效率，但旋转时仍然需要写代码为子视图自定义布局。3.布局代码在la...
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移动开发 时间：
2015-04-04 19:36:24
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211
1.题目要求You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopp...
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其他好文 时间：
2015-04-04 15:01:51
阅读次数：
130
