【数据库原理实验(openGauss)】认识DBMS系统

认识DBMS系统(openGauss)

一、openGauss安装目录

(1)集群openGauss安装目录

/opt/gaussdb/app

子目录：

• etc ：cgroup工具配置文件。
• include ：存放数据库运行所需要的头文件。
• lib ：存放数据库的库文件的目录。
• share ：存放数据库运行所需要的公共文件，如配置文件模板。

(2)集群openGauss数据目录

/gaussdb/data

子目录

• data_dnxxx ：DBnode实例的数据目录，其中主实例的目录名为“data_dnxxx”，备实例的为data_dnSxxx。xxx代表DBnode编号。

(3)集群openGauss日志目录

/var/log/gaussdb/用户名

子目录

• bin ：二进制程序的日志目录。
• gs_profile ：数据库内核性能日志目录。
• om ：OM的日志目录。例如：部分local脚本产生的日志，增删数据库节点接口的日志，gs_om接口的日志，前置接口的日志，节点替换接口的日志等。
• pg_audit ：数据库审计日志目录。
• pg_log ：数据库节点实例的运行日志目录。

(4)集群openGauss系统工具目录

/opt/huawei/wisequery

子目录

• script ：用于openGauss用户进openGauss管理的脚本文件。
• lib ：bin目录下的二进制文件依赖的库文件。

二、连接数据库

1.切换用户环境

在数据库主节点服务器上，切换至omm（数据库安装用户）操作系统用户环境。

su - omm 

2.启动数据库服务

• 启动服务命令：

  gs_om -t start
  

  

• 查看服务是否启动命令：

  gs_om -t status
  

  

• 连接数据库命令：

  • 连接默认数据库

    gsql -d postgres -p 26000 -r 
    

    • postgres为openGauss安装完成后默认生成的数据库。初始可以连接到此数据库进行新数据库的创建。
    • 26000为数据库主节点的端口号，需根据openGauss的实际情况做替换，请确认连接信息获取。
    • gsql是openGauss数据库提供的命令行方式的数据库连接工具。

    

  • 使用其他用户连接到指定数据库

    gsql -d 数据库名 -p 26000 -U 用户名 -W 密码  -r
    

三、openGauss数据库基本操作

注意postgres=#为默认数据库，其后为操作指令

• (1)查看数据库对象

  • 查看帮助信息：

    `postgres=#` \?
    

  • 切换数据库：

    `postgres=#` \c dbname
    

  • 列举数据库：
    使用\l元命令查看数据库系统的数据库列表。

    `postgres=#` \l
    

    使用如下命令通过系统表pg_database查询数据库列表。

    `postgres=#` SELECT datname FROM pg_database;
    

  • 列举表：

    `postgres=#` \dt
    

  • 列举所有表、视图和索引：

    `postgres=#` \d+
    

    使用gsql的\d+命令查询表的属性。

    `postgres=#` \d+ tablename
    

  • 查看表结构：

    `postgres=#` \d tablename
    

  • 列举schema：

    `postgres=#` \dn
    

  • 查看索引：

    `postgres=#` \di
    

  • 查询表空间：
    使用gsql程序的元命令查询表空间。

    `postgres=#` \db
    

    检查pg_tablespace系统表。如下命令可查到系统和用户定义的全部表空间。

    `postgres=#` SELECT spcname FROM pg_tablespace;
    

  • 查看数据库用户列表：

    `postgres=#` SELECT * FROM pg_user;
    

  • 查看用户属性：

    `postgres=#` SELECT * FROM pg_authid;
    

  • 查看所有角色：

    `postgres=#` SELECT * FROM PG_ROLES;
    

• (2)其他操作

  • 查看openGauss支持的所有SQL语句：

    `postgres=#`\h
    

  • 切换数据库：

    `postgres=#` \c dbname
    

  • 切换用户：

    `postgres=#` \c – username
    

  • 退出数据库：

    `postgres=#` \q
    

附录：

1.openGauss帮助信息

General
  \copyright             show FusionInsight LibrA usage and distribution terms
  \g [FILE] or ;         execute query (and send results to file or |pipe)
  \h(\help) [NAME]              help on syntax of SQL commands, * for all comman
ds
  \parallel [on [num]|off] toggle status of execute (currently off)
  \q                     quit gsql

Query Buffer
  \e [FILE] [LINE]       edit the query buffer (or file) with external editor
  \ef [FUNCNAME [LINE]]  edit function definition with external editor
  \p                     show the contents of the query buffer
  \r                     reset (clear) the query buffer
  \w FILE                write query buffer to file

Input/Output
  \copy ...              perform SQL COPY with data stream to the client host
  \echo [STRING]         write string to standard output
  \i FILE                execute commands from file
  \i+ FILE KEY           execute commands from encrypted file
  \ir FILE               as \i, but relative to location of current script
  \ir+ FILE KEY          as \i+, but relative to location of current script
  \o [FILE]              send all query results to file or |pipe
  \qecho [STRING]        write string to query output stream (see \o)

Informational
  (options: S = show system objects, + = additional detail)
  \d[S+]                 list tables, views, and sequences
  \d[S+]  NAME           describe table, view, sequence, or index
  \da[S]  [PATTERN]      list aggregates
  \db[+]  [PATTERN]      list tablespaces
  \dc[S+] [PATTERN]      list conversions
  \dC[+]  [PATTERN]      list casts
  \dd[S]  [PATTERN]      show object descriptions not displayed elsewhere
  \ddp    [PATTERN]      list default privileges
  \dD[S+] [PATTERN]      list domains
  \ded[+] [PATTERN]      list data sources
  \det[+] [PATTERN]      list foreign tables
  \des[+] [PATTERN]      list foreign servers
  \deu[+] [PATTERN]      list user mappings
  \dew[+] [PATTERN]      list foreign-data wrappers
  \df[antw][S+] [PATRN]  list [only agg/normal/trigger/window] functions
  \dF[+]  [PATTERN]      list text search configurations
  \dFd[+] [PATTERN]      list text search dictionaries
  \dFp[+] [PATTERN]      list text search parsers
  \dFt[+] [PATTERN]      list text search templates
  \dg[+]  [PATTERN]      list roles
  \di[S+] [PATTERN]      list indexes
  \dl                    list large objects, same as \lo_list
  \dL[S+] [PATTERN]      list procedural languages
  \dn[S+] [PATTERN]      list schemas
  \do[S]  [PATTERN]      list operators
  \dO[S+] [PATTERN]      list collations
  \dp     [PATTERN]      list table, view, and sequence access privileges
  \drds [PATRN1 [PATRN2]] list per-database role settings
  \ds[S+] [PATTERN]      list sequences
  \dt[S+] [PATTERN]      list tables
  \dT[S+] [PATTERN]      list data types
  \du[+]  [PATTERN]      list roles
  \dv[S+] [PATTERN]      list views
  \dE[S+] [PATTERN]      list foreign tables
  \dx[+]  [PATTERN]      list extensions
  \l[+]                  list all databases
  \sf[+] FUNCNAME        show a function's definition
  \z      [PATTERN]      same as \dp

Formatting
  \a                     toggle between unaligned and aligned output mode
  \C [STRING]            set table title, or unset if none
  \f [STRING]            show or set field separator for unaligned query output
  \H                     toggle HTML output mode (currently off)
  \pset NAME [VALUE]     set table output option
                         (NAME := {
     format|border|expanded|fieldsep|fieldsep_zero|footer|null|
                         numericlocale|recordsep|recordsep_zero|tuples_only|title|tableattr|pager})
  \t [on|off]            show only rows (currently off)
  \T [STRING]            set HTML <table> tag attributes, or unset if none
  \x [on|off|auto]       toggle expanded output (currently off)

Connection
  \c[onnect] [DBNAME|- USER|- HOST|- PORT|-]
                         connect to new database (currently "postgres")
  \encoding [ENCODING]   show or set client encoding
  \conninfo              display information about current connection

Operating System
  \cd [DIR]              change the current working directory
  \setenv NAME [VALUE]   set or unset environment variable
  \timing [on|off]       toggle timing of commands (currently off)
  \! [COMMAND]           execute command in shell or start interactive shell

Variables
  \prompt [TEXT] NAME    prompt user to set internal variable
  \set [NAME [VALUE]]    set internal variable, or list all if no parameters
  \unset NAME            unset (delete) internal variable

Large Objects
  \lo_export LOBOID FILE
  \lo_import FILE [COMMENT]
  \lo_list
  \lo_unlink LOBOID      large object operations

2.openGauss支持的所有SQL语句

Available help:
  ABORT                             CREATE TEXT SEARCH CONFIGURATION
  ALTER APP WORKLOAD GROUP          CREATE TEXT SEARCH DICTIONARY
  ALTER APP WORKLOAD GROUP MAPPING  CREATE TRIGGER
  ALTER AUDIT POLICY                CREATE TYPE
  ALTER DATA SOURCE                 CREATE USER
  ALTER DATABASE                    CREATE VIEW
  ALTER DEFAULT PRIVILEGES          CREATE WEAK PASSWORD DICTIONARY
  ALTER DIRECTORY                   CREATE WORKLOAD GROUP
  ALTER EXTENSION                   CURSOR
  ALTER FOREIGN TABLE               DEALLOCATE
  ALTER FOREIGN TABLE FOR HDFS      DECLARE
  ALTER FUNCTION                    DELETE
  ALTER GROUP                       DO
  ALTER INDEX                       DROP APP WORKLOAD GROUP
  ALTER LARGE OBJECT                DROP APP WORKLOAD GROUP MAPPING
  ALTER MASKING POLICY              DROP AUDIT POLICY
  ALTER NODE                        DROP CLIENT MASTER KEY
  ALTER NODE GROUP                  DROP COLUMN ENCRYPTION KEY
  ALTER RESOURCE LABEL              DROP DATA SOURCE
  ALTER RESOURCE POOL               DROP DATABASE
  ALTER ROLE                        DROP DIRECTORY
  ALTER ROW LEVEL SECURITY POLICY   DROP EXTENSION
  ALTER SCHEMA                      DROP FOREIGN TABLE
  ALTER SEQUENCE                    DROP FUNCTION
  ALTER SERVER                      DROP GROUP
  ALTER SESSION                     DROP INDEX
  ALTER SYNONYM                     DROP MASKING POLICY
  ALTER SYSTEM KILL SESSION         DROP MATERIALIZED VIEW
  ALTER SYSTEM SET                  DROP NODE
  ALTER TABLE                       DROP NODE GROUP
  ALTER TABLE PARTITION             DROP OWNED
  ALTER TABLESPACE                  DROP PROCEDURE
  ALTER TEXT SEARCH CONFIGURATION   DROP RESOURCE LABEL
  ALTER TEXT SEARCH DICTIONARY      DROP RESOURCE POOL
  ALTER TRIGGER                     DROP ROLE
  ALTER TYPE                        DROP ROW LEVEL SECURITY POLICY
  ALTER USER                        DROP SCHEMA
  ALTER VIEW                        DROP SEQUENCE
  ALTER WORKLOAD GROUP              DROP SERVER
  ANALYSE                           DROP SYNONYM
  ANALYZE                           DROP TABLE
  ANONYMOUS BLOCK                   DROP TABLESPACE
  BEGIN                             DROP TEXT SEARCH CONFIGURATION
  CALL                              DROP TEXT SEARCH DICTIONARY
  CHECKPOINT                        DROP TRIGGER
  CLEAN CONNECTION                  DROP TYPE
  CLOSE                             DROP USER
  CLUSTER                           DROP VIEW
  COMMENT                           DROP WEAK PASSWORD DICTIONARY
  COMMIT                            DROP WORKLOAD GROUP
  COMMIT PREPARED                   END
  COPY                              EXECUTE
  CREATE APP WORKLOAD GROUP         EXECUTE DIRECT
  CREATE APP WORKLOAD GROUP MAPPING EXPLAIN
  CREATE AUDIT POLICY               FETCH
  CREATE BARRIER                    GRANT
  CREATE CLIENT MASTER KEY          INSERT
  CREATE COLUMN ENCRYPTION KEY      LOCK
  CREATE DATA SOURCE                MERGE
  CREATE DATABASE                   MOVE
  CREATE DIRECTORY                  PREPARE
  CREATE EXTENSION                  PREPARE TRANSACTION
  CREATE FOREIGN TABLE              REASSIGN OWNED
  CREATE FUNCTION                   REFRESH MATERIALIZED VIEW
  CREATE GROUP                      REINDEX
  CREATE INDEX                      RESET
  CREATE MASKING POLICY             REVOKE
  CREATE MATERIALIZED VIEW          ROLLBACK
  CREATE NODE                       ROLLBACK PREPARED
  CREATE NODE GROUP                 SELECT
  CREATE PROCEDURE                  SELECT INTO
  CREATE RESOURCE LABEL             SET
  CREATE RESOURCE POOL              SET CONSTRAINTS
  CREATE ROLE                       SET ROLE
  CREATE ROW LEVEL SECURITY POLICY  SET SESSION AUTHORIZATION
  CREATE SCHEMA                     SET TRANSACTION
  CREATE SEQUENCE                   SHOW
  CREATE SERVER                     START TRANSACTION
  CREATE SYNONYM                    TRUNCATE
  CREATE TABLE                      UPDATE
  CREATE TABLE AS                   VACUUM
  CREATE TABLE PARTITION            VALUES
  CREATE TABLESPACE