SQL>insertintotuser.t1selecttuser.t1_seq.nextval,'zhang',dbms_random.string('A',32),dbms_random.string('x',65536*20),sysdatefromdual;1rowcreated.SQL>commit;Commitcomplete.SQL>updatetuser.t1setdescription='xxxxxx
let’s see how many rows the table contains. To do this, we’ll execute the SELECT query with the COUNT(*) function that returns the number of all rows in the table.
This is a modal window. No compatible source was found for this media. PL/SQL Program Units A PL/SQL unit is any one of the following − PL/SQL block Function Package Package body Procedure Trigger Type Type body Each of these units will be discussed in the following chapters. ...
MariaDB supports SHOW statements to quickly list all objects of a certain type (tables, views, triggers...). Most SHOW statements support a LIKE clause to filter data. For example, to list the tables in the current database whose name begins with 'wp_': SHOW TABLES LIKE 'wp\_%'; ...
Before Delete Trigger begin tran does the row level lock or table level lock Begin Transaction with If Condition BEGIN TRANSACTION within TRY - CATCH or vice versa Best practice to handle the paging and performance in SQL Stored procedure Best Practice: Use of semi-colon to terminate statements;...
trigger_event : 触发器的监听事件。取值为 INSERT、UPDATE 或DELETE。 table_name : 触发器的监听目标。指定在哪张表上建立触发器。 FOR EACH ROW: 行级监视,Mysql 固定写法,其他 DBMS 不同。 trigger_statements: 触发器执行动作。是一条或多条 SQL 语句的列表,列表内的每条语句都必须用分号 ; 来结尾。 当...
The SQL statement specified by the second parameter of the function cannot trigger cross-node query. Otherwise, an error is reported. The SQL statement specified by the second parameter of the function can only be a SELECT, UPDATE, DELETE, or INSERT statement. The returning statement is not ...
pg_get_triggerdef(trigger_oid, pretty_bool) geometric type conversion function: line(point, point) pg_node_tree sql create table clause: inherits tables. syntax inherits ( parent_table [, ... ] ) create table column constraints: use references reftable references reftable [ ( refcolumn ) ...
DDL is used to define or modify objects in the database, where database objects include tables, indexes, views, databases, stored procedures, triggers, custom functions, etc. The following operations are mainly involved. (1) Define databases: create a database (CREATE DATABASE), modify a dat...
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