test=# insert into tbl_check (a,b) values(-1,'ab'); ERROR: new row for relation "tbl_check" violates check constraint "ck_tbl_check_a" DETAIL: Failing row contains (-1, ab). test=# insert into tbl_check (a,b) values(1,'ac'); ERROR: new row for relation "tbl_check" viola...
ERROR: new row for relation "tbl_check" violates check constraint "ck_tbl_check_a" DETAIL: Failing row contains (-1, ab). test=# insert into tbl_check (a,b) values(1,'ac'); ERROR: new row for relation "tbl_check" violates check constraint "ck_tbl_check_b" DETAIL: Failing row ...
近期同事在讨论如何在PostgreSQL中一张大表,添加一个带有not null属性的,且具有缺省值的字段,并且要求在秒级完成。因为此,有了以下的实验记录:首先我们是在PostgreSQL 10下做的实验: postgres=# select version(); ...
CREATE TABLE public.pet_ ( species_ text NOT NULL, name_ text NOT NULL, date_of_birth_ text NOT NULL, uuid_ uuid NOT NULL DEFAULT uuid_generate_v1(), -- <=== CONSTRAINT pet_pkey_ PRIMARY KEY (uuid_) ) WITH ( OIDS=FALSE ); ALTER TABLE public.pet_ OWNER TO postgres; Query T...
CREATE TABLE test=# insert into tbl_null (a,b) values(1,'1');INSERT 0 1 test=# insert into tbl_null (a) values(2);INSERT 0 1 test=# insert into tbl_null (b) values('3');ERROR: null value in column "a" violates not-null constraint DETAIL: Failing row contains (null, 3...
5. Alter Default in MySQL Finally, let’s explore MySQL. TheALTER TABLEin MySQL is identical to PostgreSQL: ALTER TABLE Course ALTER COLUMN is_active SET DEFAULT 'Yes'; MySQL also doesn’t require us to check or remove an existing default constraint before changing it. We can also remove ...
defup# Lower PostgreSQL's lock timeout to avoid statement queueing.execute"SET lock_timeout TO '5s'"# The lock_timeout duration is customizable.# Add the column without the default value and the not-null constraint.add_column:users,:admin,:boolean# Set the column's default value.change_...
alter table tab_testadd col_test NOT NULL CONSTRAINT DFtab_test_col_test DEFAULT 1 引用:http://www.uzzf.com/news/2275.html
To remove the default from a column in MySQL: ALTERTABLEemployeeALTERemployment_statusDROPDEFAULT; This will remove the default constraint from the employment_status column. PostgreSQL Create Table You can add a DEFAULT constraint to a column in a table when you create it inPostgreSQL. To do thi...
其实最近看代码，发现好多地方实体以及数据库DDL语句关于空值和默认值不是很统一，有时候排查问题会让你很...