We can set constraints to the table with the help of queries SQL> SELECT DBMS_METADATA.GET_DEPENDENT_DDL ('REF_CONSTRAINT','OBJECT_NAME','SCHEMA_NAME') from dual We can grant access to the system or user with the help of the DBMS_metadata package. SQL> SELECT DBMS_METADATA.GET_GRANTED...
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So far we have discussed all the five categories of SQL Commands i.e DCL, DML, DDL, TCL and DQL and it’s subtypes. We’ve gone through each command in detail with its syntax and example that will assist you in writing queries. The SQL commands’ allows you to construct and manipulate...
如果允许多个查询（allowMultiQueries=true用于MySQL），则用户可能会执行某些执行更新的操作并选择某些操作...
SQL> exec dbms_stats.gather_index_stats(ownname=>null,indname=>'ZIGGY_CODE_I'); PL/SQL procedure successfully completed. SQL> select partition_name, num_rows, clustering_factor from dba_ind_partitions where index_name='ZIGGY_CODE_I'; PARTITION_NAME NUM_ROWS CLUSTERING_FACTOR --- --- -...
To discover which objects are not maintained by SQL Apply, you must run two queries. The first query is as follows: Copy SQL> SELECT OWNER FROM DBA_LOGSTDBY_SKIP WHERE STATEMENT_OPT = 'INTERNAL SCHEMA'; This returns all schemas that are considered to be internal. User tables...
Alter command is a DDL command used for altering the table structure like adding more columns, or changing datatype of any existing column, or to drop a column in a table etc.
max_tasks_in_queue:分布式DDL队列中可以保留的最大记录数,默认为1000条。 将以上参数加入config.xml的<distributed_ddl>一节即可。 <distributed_ddl><!-- Path in ZooKeeper to queue with DDL queries --><path>/clickhouse/task_queue/ddl</path><cleanup_delay_period>60</cleanup_delay_period><task_max...
· Insignificant whitespace is generally ignored in SQL statements and queries, making it easier to format SQL code for readability. sql语言被细分为几个语言元素,其中包括: · 条款这是语句和查询的组成部分。(在某些情况下,这些是可选的)[19] · 表达它可以产生标量值,或表由柱和行数据 · 谓词指定...