Index Organized table by itself is a B-tree index. Index key is the primary key and the rest of columns are index values. The rows are stored in the primary key order. IOT provides fast access to a specific row by primary ke or the prefix of primary…

heap 和iot 对比 OBJECT_NAME OBJECT_TYPE -------------------------------------------------------------------------------------------------------------------------------- ------------------- T2 TABLE SYS_C0022204 INDEX T1 TABLE SYS_IOT_TOP_102688 INDEX OB…

<pre name="code" class="html"> create table t1 (id char(10) primary key,a1 char(10),a2 char(10)); begin for i in 1 .. 1000 loop insert into t1 values(i,i,'a'||i); end loop ; commit; end; BEGIN DBMS_STATS.GATHER_TABLE_STATS(ownnam…

SQL> create user scan identified by scan default tablespace users; User created. SQL> grant dba to scan; Grant succeeded. create table t1 (id char(10) primary key,a1 char(10),a2 char(10)); begin for i in 1 .. 25 loop insert into t1 values(i,i,'a'||i…

1. 创建heap 表: create table t1 (id char(10) primary key,a1 char(10),a2 char(10),a3 char(10)); SQL> select OBJECT_NAME,OBJECT_TYPE from user_objects; OBJECT_NAME OBJECT_TYPE ------------------------------ ------------------- T1 TABLE SYS_C0021515 INDEX…

http://blog.csdn.net/a740169405/article/details/53610689 Shallow Heap 和 Retained Heap的区别 https://i.cnblogs.com/EditPosts.aspx?postid=8448572 http://blog.51cto.com/supercharles888/1347144…

SQL> select * from (select * from t1 order by id ) where rownum<20; ID A1 A2 A3 ---------- ---------- ---------- ---------- 1 1 1 a1 10 10 10 a10 100 100 100 a100 1000 1000 1000 a1000 10000 10000 10000 a10000 1001 1001 1001 a1001 1002 1002 1002 a100…

1.在Hive里面创建一个表: hive> create table wyp(id int,    > name string,    > age int,    > tele string)    > ROW FORMAT DELIMITED    > FIELDS TERMINATED BY '\t'    > STORED AS TEXTFILE;OKTime taken: 0.759 seconds 2.这样我们就在Hive里面创建了一张普通的表,现在给这…

堆栈的概念: 堆栈是两种数据结构.堆栈都是一种数据项按序排列的数据结构,只能在一端(称为栈顶(top))对数据项进行插入和删除.在单片机应用中,堆栈是个特殊的存储区,主要功能是暂时存放数据和地址,通常用来保护断点和现场.要点:堆,队列优先,先进先出(FIFO—first in first out).栈,先进后出(FILO—First-In/Last-Out). 堆和栈的区别: 一.堆栈空间分配区别: 1.栈(操作系统):由操作系统自动分配释放 ,存放函数的参数值,局部变量的值等.其操作方式类似于…

一个由C/C++编译的程序占用的内存分为以下几个部分    1.栈区(stack)—   由编译器自动分配释放   ,存放函数的参数值,局部变量的值等.其    操作方式类似于数据结构中的栈.    2.堆区(heap)   —   一般由程序员分配释放,   若程序员不释放,程序结束时可能由OS回    收   .注意它与数据结构中的堆是两回事,分配方式倒是类似于链表,呵呵.    3.全局区(静态区)(static)—,全局变量和静态变量的存储是放在一块的,初始化的    全局变量和静态变量…