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$ sqlplus / as sysdba
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Name Null? Type
----------------------------------------- -------- ----------------------------
USERNAME NOT NULL VARCHAR2(30)
USER_ID NOT NULL NUMBER
PASSWORD VARCHAR2(30)
ACCOUNT_STATUS NOT NULL VARCHAR2(32)
LOCK_DATE DATE
EXPIRY_DATE&
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When queried, virtual columns appear to be normal table columns, but
their values are derived rather than being stored on disc. The syntax
for defining a virtual column is listed below.
column_name [datatype] [GENERATED ALWAYS] AS (expression) [VIRTUAL]
If the datatype is omitted, it is determin ......
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1¡¢´´½¨±ít1 £ºcreate table t1 (id number,name nvarchar(8))£»
2¡¢´´½¨ÐòÁÐ £ºCREATE SEQUENCE t1_id INCREMENT BY 1 START WITH 1 MAXVALUE
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CREATE TRIGGER tig_insert_t1
BEFORE INSERT ON "YINZQ"."T1"
begin
if (:new.id is null) then
......