常见的数据库对象
表:基本的数据存储集合,由行和列组成
视图:从表中抽出逻辑上相关的数据集合
序列:提供有规律的数值
索引:提高查询效率
同义词:给对象起别名
(索引和同义词了解即可)
序列sequences
可供多个用户用来产生唯一数值的数据库对象
自动提供唯一的数值
共享对象
主要用于提供主键值
将序列值装入内存可以提高访问效率
如何和创建序列
CREA...
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数据库 时间:
2015-02-05 20:32:01
阅读次数:
241
题目大意:
Hzz loves aeroplane chess very much. The chess map contains N+1 grids labeled from 0 to N. Hzz starts at grid 0. For each step he throws a dice(a dice have six faces with equal probability to f...
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其他好文 时间:
2015-02-04 16:32:06
阅读次数:
156
DescriptionThough ZCC has many Fans, ZCC himself is a crazy Fan of a coder, called "Memset137".It was on Codefires(CF), an online competitive programm...
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其他好文 时间:
2015-02-01 20:16:10
阅读次数:
238
Description Dragon loves lottery, he will try his luck every week. One day, the lottery company brings out a new form of lottery called accumulated...
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其他好文 时间:
2015-01-31 14:33:10
阅读次数:
190
KMP算法KMP的基处题目,数字数组的KMP算法应用。主要是模式串的处理,当模式串内有重复时,模式串向左回溯重复的点的位置(next[])。Problem DescriptionGiven two sequences of numbers : a[1], a[2], ...... , a[N], a...
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其他好文 时间:
2015-01-31 00:03:28
阅读次数:
170
A - Number Sequence
Crawling in process...
Crawling failed
Time Limit:5000MS
Memory Limit:32768KB 64bit IO Format:%I64d & %I64u
Description
Given two sequences of numbers : a[1...
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其他好文 时间:
2015-01-29 17:52:50
阅读次数:
240
[This post is by Gilles Debunne, an engineer in the Android group who loves to get multitasked. — Tim Bray]A good practice in creating responsive appl...
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其他好文 时间:
2015-01-28 14:34:20
阅读次数:
180
Suppose that all the keys in a binary tree are distinct positive integers. Given the postorder and inorder traversal sequences, you are supposed to ou...
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其他好文 时间:
2015-01-28 14:32:56
阅读次数:
152
序列
select * from user_sequences
select last_number from user_sequences where sequence_name='T_JGXX_POLY_SEQ';
alter sequence T_JGXX_POLY_SEQ increment by 1;
SELECT T_JGXX_POLY_SEQ.NEXTVAL FROM DUAL;...
分类:
数据库 时间:
2015-01-27 18:24:39
阅读次数:
171
题意:给定n个点m条边的无向图,每次必须沿着LOVE走,到终点时必须是完整的LOVE,且至少走出一个LOVE,问这样情况下最短
路是多少,在一样短情况下最多的LOVE个数是多少。注意:有自环!(见底下的数据)
思路:其实本质就是个最短路,用spfa就好。注意自环的特殊处理,详见代码:
/*****************************************************...
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其他好文 时间:
2015-01-27 09:28:00
阅读次数:
162