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First, build table 1, ID: Each table to set a meaningless ID, preferably an int (unsigned), much better than varchar performance, set to self-increment better. Exceptions to foreign key conditions. 2. Field type (1) try not to use NULL, especially

Symbol tableEach package has its own symbol table, which is a hash table. The keyword is the variable name, file handle, directory handle, and subroutine in the package. The value is typeglob. Each symbol is assigned a typeglob (* X), which

A data dictionary is a collection of metadata, such as created tables, columns, constraints, triggers, and so on, which are metadata that need to be saved in the database. In addition, some of Oracle's own database objects, such as directories,

Blocking blocked and racblocked in RAC Environment The blocking in the RAC environment is different from that in a single instance, because we need to consider the session in different instances. That is to say, the corresponding strain of the

In 10 Gb, enqueueTX waits for four types: 1.enq: TX In 10g, enqueue TX waits are divided into four categories: 1. enq: TX-row lock contention 2. enq: TX-index contention 3. enq: TX-ITL 4. enq: T In 10g, the enqueue TX wait is divided into four

Exception:The exception is a feature that is provided by the programming language to enhance the robustness and fault tolerance of the program.Exceptions are divided into:System exceptionsCustom exceptionsSystem exceptions are divided

The blocking in the RAC environment is different from that in a single instance, because we need to consider the session in different instances. That is to say, the v $ session and v $ lock in the previous query should change accordingly. The

1 Special Permissions Set_uid[[email protected] ~]# ls-l/usr/bin/passwd when s appears on the file owner's X permission description is set_uid-rwsr-xr-x. 1 root root 27832 June 2014/usr/bin/passwdset_uid is an ordinary user who temporarily owns the

Resolving index failure when Oracle Partition Table deletes partition data I. Description Today, we have a small task to delete some data. Haha, please be happy first. Because the data table to be deleted is the partition table that I previously

Socket programming 1. Basic