CREATE TABLE student ( id integer, name character varying(50), age integer ) WITH (orientation=row, compression=no) DISTRIBUTE BY HASH(id); CREATE TABLE stuscore( id integer, score integer ) WITH (orientation=ro
1) 理解索引的概念与类型。 2) 掌握创建、更改、删除索引的方法。 3) 掌握维护索引的方法。 在student表的student_name字段创建名为index_name的索引。 用ALTER TABLE语句为course表的course_name创建名为index_cname的(唯一性)索引。(add unique index) 删除student表上的index_name索引。... ...
Choose a primary key for each entity (e.g.,student_idfor aStudententity). Create the Tables in SQL (Optional Test) Generate SQLCREATE TABLEstatements based on your design. Run the SQL scripts on your preferred DBMS to ensure correctness. Example ER Diagram Entities: Student, Course, Enrollmen...
type t_table is table of varchar2(10) indexby BINARY_integer;MyTab t_table;beginMyTab(1) := 'A';MyTab(2) := 'B';MyTab(3) := 'C';DBMS_OUTPUT.PUT_LINE('First index:'||' '|| mytab(1) ||' ');end;--DECLARETYPE t_StudentTable IS TABLE OF students%ROWTYPE INDEXBY BINARY...
create type 自定义Object类型A as object( 字段1 类型1, 字段2 类型2 ); 与 type 自定义表类型B is table of 类型 和 type 自定义Object类型B is record( 字段1 类型1, 字段2 类型2 ); 自定义类型一般分为两中,object类型和table类型.object类似于一个recored,可以表示一个表的一行数据, ...
4、For 循环For ... in ... LOOP --执行语句 end LOOP; (1)循环遍历游标 create or replace procedure test() as Cursor cursor is select name from student; name varchar(20); begin for name in cursor LOOP --开始循环 begin dbms_output.putline(name); ...
mysql中You can't specify target table for update in FROM clause错误的意思是说,不能先select出同一表中的某些值,再update这个表(在同一语句中). 例如下面这个sql: delete from tbl where id in ( select max(id) from tbl a where EXISTS ( ) ) group by tac ) 改写成下面就行了: delete from tbl...
PL/SQL Script to Implement CREATE USER and CREATE TABLE command:PL/SQL programming block allows creating users and tables. Also, several DBMS permissions can be assigned to the user as required. All the operations such as data insertion, deletion, modification can be performed...
CREATE TABLE Student( student_id INT, name VARCHAR(100), age INT); CopyThe above command will create a new table with name Student in the current database with 3 columns, namely student_id, name and age. Where the column student_id will only store integer, name will hold upto 100 ...
In the above code we have used theSQL Alter Queryto add a new column to an existing table. You can use the describe table query to see the new added column. [('name', 'varchar(255)', 'YES', '', None, ''), ('branch', 'varchar(255)', 'YES', '', None, ''), ('address...