i have a table with the ff columns and constraints :
create table newtable(
id int4 not null primary key,
lastname varchar(50) not null,
firstname varchar(50) not null,
middlename varchar(50) not null
)
I'm developing a workflow script (KNIME) that would test the schema from the source to target.
so i use the ff. code :
CREATE TABLE xtable
AS TABLE newtable;
When i checked the is_null constraints, it was set to 'yes' (but in the original table, it was set to 'no'). How can i include the constraints using the above-mentioned code script?
It appears that you can't achieve it with the current approach. The best option I know is the following query:
CREATE TABLE xtable (LIKE newtable INCLUDING ALL);
INSERT INTO xtable SELECT * FROM newtable;
You can read about this syntax here.
Related
I created an in memory H2 database with JDBC URL
jdbc:h2:~/test;MODE=PostgreSQL;DATABASE_TO_LOWER=TRUE;DEFAULT_NULL_ORDERING=HIGH
The H2 web console refuses to let me do an auto_increment. I've seen serial for Postgres, but that doesn't work either.
At it's simplest, it hates:
create table test(id bigint auto_increment);
Syntax error in SQL statement "create table test(id bigint [*]auto_increment)"; expected "ARRAY, INVISIBLE, VISIBLE, NOT NULL, NULL, AS, DEFAULT, GENERATED, ON UPDATE, NOT NULL, NULL, DEFAULT ON NULL, NULL_TO_DEFAULT, SEQUENCE, SELECTIVITY, COMMENT, CONSTRAINT, COMMENT, PRIMARY KEY, UNIQUE, NOT NULL, NULL, CHECK, REFERENCES, ,, )"; SQL statement:
create table test(id bigint auto_increment) [42001-214] 42001/42001 (Help)
Why do I care:
My code base was failing with NULL not allowed for column "REV". I'm using JPA/Hibernate + Liquibase. In order to try the suggestions at
Hibernate Envers + Liquibase: NULL not allowed for column "REV"
I'm trying to add an auto_increment to my Liquibase changelog file.
You can use the SQL Standard's generation clause GENERATED ALWAYS AS IDENTITY. For example:
create table test (
id bigint generated always as identity,
name varchar(10)
);
See PostgreSQL Example.
It works the same way in H2. For example:
create table test(id bigint generated always as identity, name varchar(10));
insert into test (name) values ('Chicago') ;
select * from test;
Result:
ID NAME
-- -------
1 Chicago
If I want to do something relatively complicated - something usually done by a stored procedure. Is it possible to make it automatic using a VIEW?
My specific case:
I want output table = input table A + some rows input table B. In a stored procedure, I can make a copy of table A and then INSERT INTO it, but it's not allowed in a view.
Simplified example:
input table is [test_album], and output table = input table + singer Prince.
--create test data
IF OBJECT_ID('[dbo].[test_album]', 'U') IS NOT NULL
DROP TABLE [dbo].[test_album]
CREATE TABLE [test_album] (
id int not null identity(1, 1) primary key,
singer VARCHAR(50) NULL,
album_title VARCHAR(100) NULL
)
INSERT INTO [test_album] (singer, album_title)
VALUES ('Adale', '19'),
('Michael Jaskson', 'Thriller')
--this can be executed as sql code or in stored proc
SELECT *
INTO [result_table]
FROM [test_album]
INSERT INTO [result_table] ([singer])
VALUES ('Prince')
select *
from [result_table]
--id singer album_title
--1 Adale 19
--2 Michael Jaskson Thriller
--3 Prince NULL
----as expected
But I can do this INSERT INTO inside a view.
Real-life case:
additional singers are in a table [extra_singers]
[test_album] may have many other columns (or schema may change) so it's ideal not to type all column names in the code.
--create test data
IF OBJECT_ID('[dbo].[test_album]', 'U') IS NOT NULL
DROP TABLE [dbo].[test_album]
IF OBJECT_ID('[dbo].[extra_singers]', 'U') IS NOT NULL
DROP TABLE [dbo].[extra_singers]
IF OBJECT_ID('[dbo].[result_table]', 'U') IS NOT NULL
DROP TABLE [dbo].[result_table]
CREATE TABLE [test_album] (
id int not null identity(1, 1) primary key,
singer VARCHAR(50) NULL,
album_title VARCHAR(100) NULL,
many_other_columns VARCHAR(100) NULL
)
INSERT INTO [test_album] (singer, album_title)
VALUES ('Adale', '19'),
('Michael Jaskson', 'Thriller')
CREATE TABLE [extra_singers] (
[id] int not null identity(1, 1) primary key,
[name] VARCHAR(50) NULL )
INSERT INTO [extra_singers] ([name])
VALUES ('Prince'),
('Taylor Swift')
--append [extra_singers] to [test_album]
--this can be executed as sql code or in stored proc
SELECT *
INTO [result_table]
FROM [test_album]
INSERT INTO [result_table] ([singer])
SELECT [name]
FROM [extra_singers]
Is there an alternative to this (that is automatic)?
any help's appreciated. Thank u-
a partial solution I can think of:
create view test_view as
select *
from [test_album]
union all
select 3 as id,
'Prince' as singer,
NULL as album_title
but you have to know all the column names in [test_album] and you can't let column [id] do auto-increment
So you may be misunderstanding what a view does, or what an insert is. A view is simply a wrapper around a single select query. It contains exactly one select statement, and nothing else. An insert permanently adds a row of data to a persisted table. The example you gave where you just union the row you want seems valid enough. And certainly if it's the same row you want every time, you would not want to be inserting (or even trying to insert) that row into the underlying table each time
This raises a couple questions though.
If you're always going to be unioning the same single row every time, why not jut add that row to the table?
If, lets say, you don't want that row in the underlying table, cool. But if it's always the same static values, why do you need to include it in the view? Can't it just be assumed it's there?
If it can't be assume to always be the same, you certainly don't want to be changing the VIEW body every time you need it to change. So if it is going to change and you don't want to insert it into the base table, maybe make a second table containing the values you want appended to the base table in the view. Then union the base table and the "extra values" table together instead of a single, hard coded row constructor.
How to create a table with a column which is unique, not null and not empty(Check)?
I tried below Query
CREATE TABLE Persons
(
P_Id int NOT NULL UNIQUE,
LastName nvarchar(255) NOT NULL,
FirstName nvarchar(255),
Address nvarchar(255),
City nvarchar(255),
CHECK (P_Id>0)
)
When i try to create a table with both UNIQUE and CHECK constraint its throwing following error. Is it possible to use two constraint in a single query?
Major Error 0x80040E14, Minor Error 25501
> CREATE TABLE Persons
(
P_Id int NOT NULL UNIQUE,
LastName nvarchar(255) NOT NULL,
FirstName nvarchar(255),
Address nvarchar(255),
City nvarchar(255),
CHECK (P_Id>0)
)
There was an error parsing the query. [ Token line number = 8,Token line offset = 1,Token in error = CHECK ]. I am using SQL Server 2008.
CREATE TABLE tab
(
id INT,
notnullandnotemptystr VARCHAR(10) NOT NULL UNIQUE CHECK (DATALENGTH(notnullandnotemptystr) > 0)
)
It should be some thing like this.
CREATE TABLE [dbo].[TABLE1](
[COL1] [nvarchar](50) NOT NULL UNIQUE
)
ALTER TABLE [dbo].[TABLE1] WITH CHECK
ADD CONSTRAINT [CK_TABLE1] CHECK (([COL1]<>N''))
for this problem you can use Constraint in sql server
ALTER TABLE TBL WITH CHECK ADD CONSTRAINT [CK_TBL] CHECK
(([dbo].[TBLCheckCustomeUnique](ID)=(1)))
TBLCheckCustomeUnique is a user define function that check this conditions
You can controll the uniqueness of a column or column set by the UNIQUE constraint.
The data stored in the column or column set could be checked/controlled (and forced with various rules) by the CHECK constraint.
The CHECK constraint to achieve your goal is the following:
ALTER TABLE [YourTable]
ADD CONSTRAINT CK_CheckConstraintName
CHECK (LEN([YourColumn]) >= {MinimumColumnWidth})
You can add the constraints in the CREATE TABLE statement or if the table already exists you can add it with the ALTER TABLE .. ADD CONSTRAINT statement.
I currently have a table with four columns - i wanted to add a fifth column but having some trouble.
I open the table in sql server studio management 2008 and i added the column info like so:
CREATE TABLE [dbo].[Case]
(
CaseId UNIQUEIDENTIFIER DEFAULT (newid()) NOT NULL,
CaseNumber NVARCHAR(50) NOT NULL,
CourtId INT NOT NULL,
DateOpened DATETIME NOT NULL,
)
my addition:
CREATE TABLE [dbo].[Case]
(
CaseId UNIQUEIDENTIFIER DEFAULT (newid()) NOT NULL,
CaseNumber NVARCHAR(50) NOT NULL,
CaseName NVARCHAR(50),
CourtId INT NOT NULL,
DateOpened DATETIME NOT NULL,
)
After adding CaseName column, i tried executing the table in Management Studio but i got the error message "There is already an object named 'Case' in the database."
I tried saving and then building my database hoping that the column will be added but that wasn't successful. I tried a New Query and writing the 'Alter table "case" add CaseName nvarchar(50) but again without luck. It shows that the file is changed with the new column because i saved it but after building my overall database it isn't making any changes. Any helpful tips will be great.
You want to ALTER, as follows:
ALTER TABLE [dbo].[Case] ADD CaseName NVARCHAR(50)
Better yet, you can check for the existance of the column first:
if not exists (SELECT 1 FROM sysobjects INNER JOIN syscolumns ON
sysobjects.id = syscolumns.id
WHERE sysobjects.name = N'Case' AND syscolumns.name = N'CaseName')
ALTER TABLE [dbo].[Case] ADD CaseName NVARCHAR(50)
you should try this
ALTER TABLE [dbo].[Case]
ADD CaseName NVARCHAR(50)
You are trying to create another table Case but one already exists that's why you have an error. When you want to edit a table, you have to use Alter table
Use an Alter table statement instead of Create
If you can't get the Alter statement to work for some reason, you could also drop the existing table and create a new one with the new field, but all your existing rows will be lost.
If you're using SSMS, you can Design the table instead of Edit to add the column.
ALTER is what you need to investigate (F1)
An alternative is.
Create a new table
CREATE TABLE [dbo].[Case2]
(
CaseId UNIQUEIDENTIFIER DEFAULT (newid()) NOT NULL,
CaseNumber NVARCHAR(50) NOT NULL,
CourtId INT NOT NULL,
DateOpened DATETIME NOT NULL,
newcolumn INT NULL
)
Move data from existing table into the new one
INSERT INTO [dbo].[Case2]
SELECT * FROM [dbo].[Case]
Then
DROP TABLE [dbo].[Case]
Then in management studio right-click 'Case2' and re-name it 'Case'
I recommend checking for the existence of the column prior to adding it, especially important when you work with migration scripts.
Here is how I usually do it:
IF NOT EXISTS(SELECT * FROM sys.columns WHERE Name = N'ColumnName' AND Object_ID = Object_ID(N'TableName'))
BEGIN
ALTER TABLE [dbo].TableName ADD ColumnName NVARCHAR(512) null
END
How could I set a constraint on a table so that only one of the records has its isDefault bit field set to 1?
The constraint is not table scope, but one default per set of rows, specified by a FormID.
Use a unique filtered index
On SQL Server 2008 or higher you can simply use a unique filtered index
CREATE UNIQUE INDEX IX_TableName_FormID_isDefault
ON TableName(FormID)
WHERE isDefault = 1
Where the table is
CREATE TABLE TableName(
FormID INT NOT NULL,
isDefault BIT NOT NULL
)
For example if you try to insert many rows with the same FormID and isDefault set to 1 you will have this error:
Cannot insert duplicate key row in object 'dbo.TableName' with unique
index 'IX_TableName_FormID_isDefault'. The duplicate key value is (1).
Source: http://technet.microsoft.com/en-us/library/cc280372.aspx
Here's a modification of Damien_The_Unbeliever's solution that allows one default per FormID.
CREATE VIEW form_defaults
AS
SELECT FormID
FROM whatever
WHERE isDefault = 1
GO
CREATE UNIQUE CLUSTERED INDEX ix_form_defaults on form_defaults (FormID)
GO
But the serious relational folks will tell you this information should just be in another table.
CREATE TABLE form
FormID int NOT NULL PRIMARY KEY
DefaultWhateverID int FOREIGN KEY REFERENCES Whatever(ID)
From a normalization perspective, this would be an inefficient way of storing a single fact.
I would opt to hold this information at a higher level, by storing (in a different table) a foreign key to the identifier of the row which is considered to be the default.
CREATE TABLE [dbo].[Foo](
[Id] [int] NOT NULL,
CONSTRAINT [PK_Foo] PRIMARY KEY CLUSTERED
(
[Id] ASC
) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[DefaultSettings](
[DefaultFoo] [int] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[DefaultSettings] WITH CHECK ADD CONSTRAINT [FK_DefaultSettings_Foo] FOREIGN KEY([DefaultFoo])
REFERENCES [dbo].[Foo] ([Id])
GO
ALTER TABLE [dbo].[DefaultSettings] CHECK CONSTRAINT [FK_DefaultSettings_Foo]
GO
You could use an insert/update trigger.
Within the trigger after an insert or update, if the count of rows with isDefault = 1 is more than 1, then rollback the transaction.
CREATE VIEW vOnlyOneDefault
AS
SELECT 1 as Lock
FROM <underlying table>
WHERE Default = 1
GO
CREATE UNIQUE CLUSTERED INDEX IX_vOnlyOneDefault on vOnlyOneDefault (Lock)
GO
You'll need to have the right ANSI settings turned on for this.
I don't know about SQLServer.But if it supports Function-Based Indexes like in Oracle, I hope this can be translated, if not, sorry.
You can do an index like this on suposed that default value is 1234, the column is DEFAULT_COLUMN and ID_COLUMN is the primary key:
CREATE
UNIQUE
INDEX only_one_default
ON my_table
( DECODE(DEFAULT_COLUMN, 1234, -1, ID_COLUMN) )
This DDL creates an unique index indexing -1 if the value of DEFAULT_COLUMN is 1234 and ID_COLUMN in any other case. Then, if two columns have DEFAULT_COLUMN value, it raises an exception.
The question implies to me that you have a primary table that has some child records and one of those child records will be the default record. Using address and a separate default table here is an example of how to make that happen using third normal form. Of course I don't know if it's valuable to answer something that is so old but it struck my fancy.
--drop table dev.defaultAddress;
--drop table dev.addresses;
--drop table dev.people;
CREATE TABLE [dev].[people](
[Id] [int] identity primary key,
name char(20)
)
GO
CREATE TABLE [dev].[Addresses](
id int identity primary key,
peopleId int foreign key references dev.people(id),
address varchar(100)
) ON [PRIMARY]
GO
CREATE TABLE [dev].[defaultAddress](
id int identity primary key,
peopleId int foreign key references dev.people(id),
addressesId int foreign key references dev.addresses(id))
go
create unique index defaultAddress on dev.defaultAddress (peopleId)
go
create unique index idx_addr_id_person on dev.addresses(peopleid,id);
go
ALTER TABLE dev.defaultAddress
ADD CONSTRAINT FK_Def_People_Address
FOREIGN KEY(peopleID, addressesID)
REFERENCES dev.Addresses(peopleId, id)
go
insert into dev.people (name)
select 'Bill' union
select 'John' union
select 'Harry'
insert into dev.Addresses (peopleid, address)
select 1, '123 someplace' union
select 1,'work place' union
select 2,'home address' union
select 3,'some address'
insert into dev.defaultaddress (peopleId, addressesid)
select 1,1 union
select 2,3
-- so two home addresses are default now
-- try adding another default address to Bill and you get an error
select * from dev.people
join dev.addresses on people.id = addresses.peopleid
left join dev.defaultAddress on defaultAddress.peopleid = people.id and defaultaddress.addressesid = addresses.id
insert into dev.defaultaddress (peopleId, addressesId)
select 1,2
GO
You could do it through an instead of trigger, or if you want it as a constraint create a constraint that references a function that checks for a row that has the default set to 1
EDIT oops, needs to be <=
Create table mytable(id1 int, defaultX bit not null default(0))
go
create Function dbo.fx_DefaultExists()
returns int as
Begin
Declare #Ret int
Set #ret = 0
Select #ret = count(1) from mytable
Where defaultX = 1
Return #ret
End
GO
Alter table mytable add
CONSTRAINT [CHK_DEFAULT_SET] CHECK
(([dbo].fx_DefaultExists()<=(1)))
GO
Insert into mytable (id1, defaultX) values (1,1)
Insert into mytable (id1, defaultX) values (2,1)
This is a fairly complex process that cannot be handled through a simple constraint.
We do this through a trigger. However before you write the trigger you need to be able to answer several things:
do we want to fail the insert if a default exists, change it to 0 instead of 1 or change the existing default to 0 and leave this one as 1?
what do we want to do if the default record is deleted and other non default records are still there? Do we make one the default, if so how do we determine which one?
You will also need to be very, very careful to make the trigger handle multiple row processing. For instance a client might decide that all of the records of a particular type should be the default. You wouldn't change a million records one at a time, so this trigger needs to be able to handle that. It also needs to handle that without looping or the use of a cursor (you really don't want the type of transaction discussed above to take hours locking up the table the whole time).
You also need a very extensive tesing scenario for this trigger before it goes live. You need to test:
adding a record with no default and it is the first record for that customer
adding a record with a default and it is the first record for that customer
adding a record with no default and it is the not the first record for that customer
adding a record with a default and it is the not the first record for that customer
Updating a record to have the default when no other record has it (assuming you don't require one record to always be set as the deafault)
Updating a record to remove the default
Deleting the record with the deafult
Deleting a record without the default
Performing a mass insert with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record inserts
Performing a mass update with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record updates
Performing a mass delete with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record deletes
#Andy Jones gave an answer above closest to mine, but bearing in mind the Rule of Three, I placed the logic directly in the stored proc that updates this table. This was my simple solution. If I need to update the table from elsewhere, I will move the logic to a trigger. The one default rule applies to each set of records specified by a FormID and a ConfigID:
ALTER proc [dbo].[cpForm_UpdateLinkedReport]
#reportLinkId int,
#defaultYN bit,
#linkName nvarchar(150)
as
if #defaultYN = 1
begin
declare #formId int, #configId int
select #formId = FormID, #configId = ConfigID from csReportLink where ReportLinkID = #reportLinkId
update csReportLink set DefaultYN = 0 where isnull(ConfigID, #configId) = #configId and FormID = #formId
end
update
csReportLink
set
DefaultYN = #defaultYN,
LinkName = #linkName
where
ReportLinkID = #reportLinkId