openGauss每日一练第13天| openGauss逻辑结构：表管理

课程作业

1.创建一个表（默认，不指定模式），查看该表在那个模式下

默认建表的情况下，表在public模式下

omm=#  create table t1(txt char(50));
CREATE TABLE
omm=# 
omm=# \dt t1
                        List of relations
 Schema | Name | Type  | Owner |             Storage              
--------+------+-------+-------+----------------------------------
 public | t1   | table | omm   | {orientation=row,compression=no}
(1 row)

omm=# 

2.使用一个用户连接到enmdb数据库，测试该用户可以访问不同模式中的表

使用一个用户可以访问不同模式中的表

omm=# CREATE TABLESPACE enmtbs RELATIVE LOCATION 'tablespace/enmtbs1';
CREATE TABLESPACE
omm=# CREATE DATABASE enmdb WITH TABLESPACE = enmtbs;
CREATE DATABASE
omm=# CREATE USER user1 IDENTIFIED BY 'user1@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# ALTER USER user1  SYSADMIN;
ALTER ROLE
omm=# \q
omm@modb:~$ gsql -d enmdb -U user1 -W user1@1234 -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr  )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.

enmdb=> create schema enmschm1;
CREATE SCHEMA
enmdb=> create schema enmschm2;
CREATE SCHEMA
enmdb=>  create table enmschm1.t1(col char(50));
CREATE TABLE
enmdb=>  create table enmschm2.t1(col char(50));
CREATE TABLE
enmdb=> insert into  enmschm1.t1 values('hello enmschm1');
enmdb=> INSERT 0 1
insert into  enmschm2.t1 values('hello enmschm1');
INSERT 0 1
enmdb=> select * from enmschm1.t1;
                        col                         
----------------------------------------------------
 hello enmschm1                                    
(1 row)

enmdb=> select * from enmschm2.t1;
                        col                         
----------------------------------------------------
 hello enmschm1                                    
(1 row)
enmdb=> 

3.在会话级设置模式搜索路径为:模式enmschm1,使用SchemaName.TableName的表标识方法访问表(创建表、插入数据和查询表中数据)

enmdb=>  create table t1(col char(50));
CREATE TABLE
enmdb=> insert into  t1 values('hello public'); 
INSERT 0 1
enmdb=> select * from t1; 
                       col                         
----------------------------------------------------
 hello public                                      
(1 row)

enmdb=> select * from enmschm1.t1;
                      col                         
----------------------------------------------------
 hello enmschm1                                    
(1 row)

enmdb=> 
enmdb=> set search_path to enmschm1;
SET
enmdb=> select * from t1; 
                        col                         
----------------------------------------------------
 hello enmschm1                                    
(1 row)

enmdb=> select * from enmschm1.t1;
                        col                         
----------------------------------------------------
 hello enmschm1                                    
(1 row)

enmdb=>