Before You Start

Prerequisites

GaussDB runs properly.

Procedure

1. Connect to a database. For details, see Connecting to a Database.
2. Create a database user.

   Only administrators that are created during the cluster installation can access the initial database by default. You can also create other database users.

   1	openGauss=# CREATE USER joe WITH PASSWORD "xxxxxxxxx";

   If the following information is displayed, the user has been created:

   1	CREATE ROLE

   In this case, you have created a user named joe, and the user password is xxxxxxxxxx. Run the following command to set user joe as the system administrator:

   openGauss=# GRANT ALL PRIVILEGES TO joe;

   Run the GRANT command to set related permissions. For details, see GRANT.

   Note: For details about how to create users, see Managing Users and Their Permissions.

3. Create a database.

   1	openGauss=# CREATE DATABASE db_tpcds;

   If the following information is displayed, the database has been created:

   1	CREATE DATABASE

   After creating the db_tpcds database, you can run the following command to exit the postgres database and log in to the db_tpcds database as the user you created. You can also continue using the default postgres database for more operations.

   openGauss=# \q
   gsql -d db_tpcds -p 8000 -U joe
   Password for user joe:
   gsql((GaussDB Kernel VxxxRxxxCxx build f521c606) compiled at 2021-09-16 14:55:22 commit 2935 last mr 6385 release)
   Non-SSL connection (SSL connection is recommended when requiring high-security)
   Type "help" for help.
    
   db_tpcds=> 

   Note:

   New databases are created in the pg_default tablespace by default. To specify another tablespace, run the following statement:

   1 2	openGauss=# CREATE DATABASE db_tpcds WITH TABLESPACE = hr_local; CREATE DATABASE

   hr_local indicates the tablespace name. For details about how to create a tablespace, see Creating and Managing Tablespaces.

4. Create a table.
   • Create a table named mytable that has only one column. The column name is firstcol and the column type is integer.

     1	db_tpcds=> CREATE TABLE mytable (firstcol int);

     If the DISTRIBUTE BY statement is not used to specify distribution columns, the system automatically specifies the first column as a hash distribution column and prompts you to confirm the operation. If CREATE TABLE is displayed at the end of the returned information, the table has been created.

     1 2 3

     NOTICE: The 'DISTRIBUTE BY' clause is not specified. Using 'firstcol' as the distribution column by default. HINT: Please use 'DISTRIBUTE BY' clause to specify suitable data distribution column. CREATE TABLE

   • Run the following command to insert data to the table:

     1	db_tpcds=> INSERT INTO mytable values (100);

     If the following information is displayed, the data has been inserted:

     1	INSERT 0 1

   • Run the following command to view data in the table:

     1 2 3 4 5

     db_tpcds=> SELECT * from mytable; firstcol ---------- 100 (1 row)

   Note:

   • By default, new database objects, such as the mytable table, are created in the $user schema. For more details about schemas, see Creating and Managing Schemas.
   • For more details about how to create a table, see Creating and Managing Tables.
   • In addition to the created tables, a database contains many system catalogs. These system catalogs contain cluster installation, GaussDB queries and processes. You can collect information about the database by querying system catalogs. For details, see Querying a System Catalog.

     GaussDB supports hybrid row-column store, providing high query performance for interaction analysis in complex scenarios. For details about how to select a storage method, see Planning a Storage Model.