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足彩常用缩水算法-6-32
6个310,8个31,中14包13.3333333333333333333311133333333333133113333333333111133333333331313133333333131131333333331133113333333333131133333333113133133333333311331333333331331313333333131313133333331333...
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The Power of EXECUTE IMMEDIATE and CASE WHEN[akadia]
Never do procedurally what you can do in a single SQL statement. If you have a typical CASE construct you can use EXECUTE IMMEDIATE with a CASE statement.Suppose you have the following UPDATE:DECLARE ...
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哈希算法
哈希算法将任意长度的二进制值映射为固定长度的较小二进制值，这个小的二进制值称为哈希值。哈希值是一段数据唯一且极其紧凑的数值表示形式。如果散列一段明文而且哪怕只更改该段落的一个字母，随后的哈希都将产生不...
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CREATE TABLE AS and LONG RAW[from akadia]
Long Raw data types cannot be included in the CREATE TABLE AS syntax. This is documented in the Oracle 7.3 or 8.0 Server SQL Reference Guide 'AS subquery' clause explanation of the CREATE TABLE syntax...
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最近优化了两个很烂的系统
已经用了好几年了,数据量的增长较快,不做优化就只能换新的硬件了.全表扫描的语句很多,简单地创建合适的索引/修改部分代码后就快了很多.只有两个东西值得说一下:1. 某些表的字段由于类型是char,导致索引无法使用,将类...
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ORA-01114: 将块写入文件 %s 时出现 IO 错误 (块 # %s) 错误
sqlplus里执行某条语句，报错：ORA-01114: 将块写入文件 %s 时出现 IO 错误 (块 # %s) 错误文件号和块号没有报出来.:(查看alert文件，后台却报出来了.
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Wait Event Enhancements in Oracle 10g
http://www.dbspecialists.com/presentations/wait_events_10g.html
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Restrict the Number of Records[akadia]
While developping database application we often have to restrict the number of records an end user can insert into a table. A simple solution is the following code fragment in the BEFORE-INSERT-FOR-EA...
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Dynamic SQL queries that return multirow result sets[akadia]
The OPEN FOR clause allows to build dynamic SQL with variable table-, or column names that return multirow result sets. Let's take a closer look at OPEN FOR and multirow queries with a concrete exampl...
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How does one enable dead connection detection ? [akadia]
Dead database connections can be detected and killed by SQL*Net if you specify the SQLNET.EXPIRE_TIME=n parameter in your SQLNET.ORA file (usually in $TNS_ADMIN). This parameter will instruct SQL*Net ...
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王小云教授简介
王小云 女，1966年8月声于山东诸城，博士，副教授。 https://www.xfocus.net/bbs/index.php?act=ST&f=2&t=39807王小云女，1966年8月声于山东诸城，博士，副教授。通讯地址：山东大学数学系，济南 250100 电话：0531-...
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含有timestamp类型数据的imp
加 commit=y 时非常慢, 不加则快20倍,看来timestamp跟lob等大字段习性一样.我的环境: p590 + aix5.3 + oracle 9206 + 3内存 + 3cpu
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9i在pl/sql方面比8i严格许多
这次数据库升级遇到一个情况:8i上可以编译的package不能在9i上编译,原因是9i要求包头的参数说明一定要和包体里的说明一致.:)
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How to escape special characters in Oracle ? [akadia]
If you want to retrieve TABLE_NAMES from ALL_TABLES where the table name is like 'ADD_' using the following query, you may notice that the query is returning ADDRESS and ADD_CODES:create table address...
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ORA-00600[ktsxaffs1]错误的解决
环境：oracle9205 rac aix5.2.0.4 hacmp5.1一台正常，一台startup时没有错误，但alert.log有如下错误:ORA-00600: 内部错误代码，参数: [ktsxaffs1], [], [], [], [], [], [], []而且产生了很多 core文件和trc文...
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Interacting with Oracle via the UNIX Korn shell [akadia]
UNIX remains a fabulous choice for hosting Oracle databases. Both technologies have proven to be more flexible and more stable for more time than most of us care to remember.The remarkable 'Korn' shel...
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谁是任正非心目中的接班人
http://info.tele.hc360.com/zt/huaweier/“虽然还没有对外公布，但华为内部已经在盛传李一男要回到华为，并且很可能是担任接班人的角色。”一位熟悉华为内情的人士说，“毕竟他被誉为技术天才，对技术趋势的把握不...
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设置口令复杂度
可以强制用户的口令符合复杂度标准。例如，可以要求口令的最小长度，限制不能是一些简单的词，至少包括一个数字或标点符号等。“create profile”和“alter profile”命令的PASSWORD_VERIFY_FUNCTION参数指定用于评...
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Tracking the progress of a long running statement[akadia]
Sometimes you run an INSERT or DELETE statement that takes a long time to complete. You have wondered how many rows have already been inserted or deleted so that you can decide whether or not to abort...
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ORA-12005: may not schedule automatic refresh for times in the past
ORA-12005 ORA-12005may not schedule automatic refresh for times in the past Cause:An attempt was made to schedule an automated snapshot refresh for a time in the past. Action:Choose a time in the futu...
