数据仓库服务 GAUSSDB(DWS)-CREATE FOREIGN TABLE (SQL on OBS or Hadoop):语法格式

时间：2024-05-09 09:29:49

语法格式

创建外表。

  
       CREATE FOREIGN TABLE [ IF NOT EXISTS ] table_name 
( [ { column_name type_name 
    [ { [CONSTRAINT constraint_name] NULL |
    [CONSTRAINT constraint_name] NOT NULL |
      column_constraint [...]} ] |
      table_constraint [, ...]} [, ...] ] ) 
    SERVER server_name 
    OPTIONS ( { option_name ' value ' } [, ...] ) 
    [ {WRITE ONLY | READ ONLY}]
    DISTRIBUTE BY {ROUNDROBIN | REPLICATION}
   
    [ PARTITION BY ( column_name ) [ AUTOMAPPED ] ] ;

其中column_constraint为：

    
         [CONSTRAINT constraint_name]
{PRIMARY KEY | UNIQUE}
[NOT ENFORCED [ENABLE QUERY OPTIMIZATION | DISABLE QUERY OPTIMIZATION] | ENFORCED]

其中table_constraint为：

    
         [CONSTRAINT constraint_name]
{PRIMARY KEY | UNIQUE} (column_name)
[NOT ENFORCED [ENABLE QUERY OPTIMIZATION | DISABLE QUERY OPTIMIZATION] | ENFORCED]