章鱼大数据

首先要明确的是：Linux下一切目标都是文件其二，Linux下常风的文件类型有哪些，使用命令：ls -l 查看文件时第一列的第一个符号就是表示这个文件的类型：Linux系统中常见的文件类型有：- （普通文件）、d(目录文件）、l (链接文件）、c（字符设备文件）、b（块设备文件）- ：普通文件：    touch 命令创建一个空文件    cp 命令从其它地方拷贝一个文件...

7、choose two:View the Exhibit and examine the structure of the PRODUCTS table.Which two tasks would require subqueries?A) Display the minimum list price for each product status.B) Display the to...

8、choose the best answer:You need to produce a report where each customer's credit limit has been incremented by $1000.In the output, the customer's last name should have the heading Name and the i...

9、choose the best answerView the Exhibit and examine the structure of the SALES and STORES tables.You want to display the store name and the total quantity sold for each item in the store.Which S...

10、choose the best answer:Examine the structure of the EMPLOYEES table:There is a parent/child relationship between EMPLOYEE_ID and MANAGER_ID.You want to display the name, joining date, and manag...

11、choose the best answer:Examine the structure of the BOOKS_TRANSACTIONS table.You want to update this table such that BOOK_ID is set to 'INVALID' for all rows where no MEMBER_IDhas been ente...

12、choose two:Examine the data in the CUSTOMERS table:You want to list all cities that have more than one customer along with the customer details.Evaluate the following query:SQL>SELECT c1.cus...

13、choose twoWhich two statements are true regarding operators used with subqueries? (Choose two.)A) =ANY and =ALL operators have the same functionality.E) The NOT IN operator is equivalent to is ...

14、choose the best answer:View the Exhibit and examine the structure of the ORDERS table.Which UPDATE statement is valid?A) UPDATE ordersSET order_date = '12-mar-2007'AND order_total = TO_NUMBER...

15、choose the best answerExamine the structure of the MEMBERS table:You want to display details of all members who reside in states starting with the letter A followedby exactly one character.Whi...

6、choose the best answer:View the Exhibit and examine the structure of the CUSTOMERS table.Evaluate the following SQL statement:SQL> SELECT cust_city, COUNT(cust_last_name)FROM customers...

5、choose two:You executed the following CREATE TABLE statement that resulted in an error:SQL> CREATE TABLE employees(emp_id NUMBER(10) PRIMARY KEY,ename VARCHAR2(20),email NUMBER(3) UNIQ...

4、choose two:View the Exhibit and examine the data in the PRODUCT_INFORMATION table.Which two tasks would require subqueries? (Choose two.)A) displaying all supplier IDs whose average list price i...

目录2.6 相对和绝对路径2.7 cd命令2.8 创建和删除目录mkdir/rmdir2.9 rm命令 1、相对和绝对路径绝对路径 从根开始的路径相对路径 不是以根开头的，相对当前目录下的路径pwd 显示当前所在目录位置cd change directory（全拼英文） 2、cd命令 cd - 进入上次所在目录cd 进入当前用户的家目录...

oracle 12C 的企业管理器做了很大改变，ORACLE逐步把本地管理的功能弱化了，不像11G的时候，启动EM的时候用命令emctl 来控制em服务的启动与停止，而到了12C,是通过一个数据库服务方式提供服务，这个服务名是：orclXDB(orcl是数据的实例名).在通过DBCA创建数据库的时候，默认是通过本地DATABASE EXPRESS方式管理数据库，数据库实例启动的情况下，可以使用...

17、choose twoView the Exhibit and examine the structure of ORDER_ITEMS and ORDERS tables.You need to remove from the ORDER_ITEMS table those rows that have an order status of 0 or 1 inthe ORDERS t...

18、choose twoWhich two statements are true regarding views? (Choose two.)A) A simple view in which column aliases have been used cannot be updated.B) The OR REPLACE option is used to change the d...

1.choose the best answerWhat is the primary difference between the relational database (RDB) andobject-oriented database (OODB) models?A) RDB allows the definition of relationships between differen...

20.choose twoExamine the description of the EMP_DETAILS table given below:Which two statements are true regarding SQL statements that can be executed on the EMP_DETAIL table?A) You cannot add a ...

choose the best answer:View the Exhibit and examine the structure of the CUSTOMERS table.CUSTOMER_VU is a view based on CUSTOMERS_BR1 table which has the same structure as CUSTOMERS table.CUSTOM...

2、choose the best answer:You need to display the first names of all customers from the CUSTOMERS table that contain thecharacter 'e' and have the character 'a' in the second last position.Which que...

3、choose the best answer:The user SCOTT who is the owner of ORDERS and ORDER_ITEMS tables issues this GRANT command:GRANT ALLON orders, order_itemsTO PUBLIC;What must be done to fix the statement...

16、choose the best answerThe PRODUCTS table has the following structure:Evaluate the following two SQL statements:SQL>SELECT prod_id, NVL2(prod_expiry_date, prod_expiry_date + 15,'')FROM produc...