随笔分类 -  数据库和SQL

摘要：1、select seq_name.nextval from dual; //假设得到结果56562、alter sequence seq_name increment by -5655; //注意是-(n-1)3、select seq_name.nextval from dual;//再查一遍，走... 阅读全文

摘要：百度文库http://wenku.baidu.com/link?url=7KyIHuoeUf1EvD5uClFNugDIT9s_dU7bu5_2XhQK4SLarHfG_dBwzhMooedQcsndHNd3UKZgM9UJDIJ3EF7EH62s2cNiZgN8aTMkUq3Gp4C已经收藏。 阅读全文

摘要：How to display 0 in conditional [group by] report in Count() SQL QueryChallenge:Let me assume this: we have two tables, one is Regions table with all region information (East, West, etc. ) and we have another table with Sales information. Now, we need to display a report with region information and 阅读全文

摘要：PL/SQL Developer 8注册码PL/SQL Developer 8.0.1.1502（或PL/SQL Developer 8.*系列SN、注册码、序列号）注册码如下：Product code: leswljrftczs7bjz8pz2kq7vzq85fu67q8f8rgg2bv Serial number: 642136713 Password: xs374ca 阅读全文

摘要：首先,可以先看一下schema和user的定义：A schema is a collection of database objects (used by a user). Schema objects are the logical structures that directly refer to the database’s data.A user is a name defined in the database that can connect to and access objects.Schemas and users help database administrators m 阅读全文

摘要：事务(Transaction)是并发控制的基本单位。 所谓事务，它是一个操作序列，这些操作要么都执行，要么都不执行，它是一个不可分割的工作单位。例如，银行转帐工作：从一个帐号扣款并使另一个帐号增款，这两个操作要么都执行，要么都不执行。 　 数据库事务必须具备ACID特性，ACID是Atomic（原子性）、Consistency（一致性）、Isolation（隔离性）和Durability（持久性... 阅读全文