Example table declaration:
CREATE TABLE Person (
ID int PRIMARY KEY,
FirstName nvarchar(255),
LastName nvarchar(255),
PhoneNumber varchar(255)
)
How can i add constraint that won't allow adding any letters into PhoneNumber?
You can use a check constraint:
alter table person add constraint chk_person_phonenumber
check (phonenumber not like '%[^0-9]%');
This says that phonenumber has no characters that are not digits.
Note that you an extend the pattern to allow spaces, hyphens, or parentheses, if you really also want those.
If you really just wanted digits, you could also use try_convert():
check (phonenumber not like '%.%' and
try_convert(decimal(38, 0), phonenumber) is not null
)
This is not as flexible for expanding the character set, though.
Related
CREATE TABLE PARTICIPANTE(
pasaporte NVARCHAR(9) NOT NULL,
nombre NVARCHAR(50) NOT NULL,
sexo CHAR(1) NOT NULL,
fecNac DATE NOT NULL,
codPais NVARCHAR(3) NOT NULL,
CONSTRAINT PK_PARTICIPANTE PRIMARY KEY (pasaporte),
CONSTRAINT FK_PAIS_PARTICIPANTE FOREIGN KEY (codPais) REFERENCES PAIS(codigo),
CONSTRAINT CHK_PASAPORTE CHECK (pasaporte like '^\[A-Z\]{3}\[0-9\]{6}$')
)
The CONSTRAINT CHK_PASAPORTE doesn't work when I try to insert the data.
The INSERT statement conflicted with the CHECK constraint "CHK_PASAPORTE". The conflict occurred in database "OMA", table "dbo.PARTICIPANTE", column 'pasaporte'.
Example
insert into PARTICIPANTE (pasaporte,nombre,sexo,fecNac,codPais) value ('JPN865653','Noguchi','F','20000104','JPN');
Can someone explain to me why this doesn't work and how can I fix it?
As I mention in the comments, SQL Server has no (in built) support for Regex, it only has basic pattern matching, which is explained in the documentation.
Fortunately, the logic you are after appears to be quite simple; 3 letters followed by 6 digits. This can be achieved with the following constraint:
ALTER TABLE dbo.PARTICIPANTE ADD CONSTRAINT CHK_PASAPORTE CHECK (pasaporte LIKE '[A-Z][A-Z][A-Z][0-9][0-9][0-9][0-9][0-9][0-9]');
Note that if you require the value to only contain uppercase values, you'll need to COLLATE the value to a collation that is case sensitive and orders upper case letters first, then lowercase, and finally alphabetically (Binary collations are one such one that does this).
I am creating a table which is like this:
CREATE TABLE Peeps
(
Name VARCHAR(255) NOT NULL,
PhoneNum BIGINT NOT NULL,
CONSTRAINT PhoneNum_Check CHECK (PhoneNum LIKE '08%')
)
Every phone number has to start with 08. However when I tried insert there's an error because LIKE can't be used for numeric (or that's what my friend said). The alternative would be using VARCHAR for PhoneNum, but this is an assignment and we have to use numeric for the phone number.
If a phone number can start with a 0 then you need to use a string:
CREATE TABLE Peeps (
Name VARCHAR(255) NOT NULL,
PhoneNum VARCHAR(255) NOT NULL,
CONSTRAINT PhoneNum_Check CHECK (PhoneNum LIKE '08%')
);
Although you can use LIKE on a number, it is highly not recommended. What happens is that the number is converted to a string. However, that string will never start with a 0 -- well, at least never when the value is greater than 1.
The code is the category of the video, it is represented by one upper case character, excluding I, O,
Q, V, Y and Z, followed by a numeric character.
So far, I took a guess and got this. Any suggestions on how to fix it?
create table channelTable (
channelID number NOT NULL,
ChannelName varchar(100) NOT NULL,
ChannelDate date NOT NULL,
UserName varchar(100) NOT NULL UNIQUE,
TopicCode varchar(4) NOT NULL);
CONSTRAINT channelID_pk PRIMARY KEY (channelID)
CONSTRAINT c_topicCode LIKE '[A-Za-z][0-9] NOT (I,O,Q,N,Y,Z)
);
Some comments:
NOT NULL is not needed for PRIMARY KEY columns.
In Oracle, use VARCHAR2().
Then, I would suggests regular expressions. If the value is supposed to be exactly two characters, then declare it as such:
create table channelTable (
channelID number,
ChannelName varchar(100) NOT NULL,
ChannelDate date NOT NULL,
UserName varchar2(100) NOT NULL UNIQUE,
TopicCode char(2) NOT NULL;
CONSTRAINT channelID_pk PRIMARY KEY (channelID)
CONSTRAINT check (REGEXP_LIKE(c_topicCode, '^[A-HJ-NPR-UYZ][0-9]$')
);
Or perhaps more simply:
CONSTRAINT REGEXP_LIKE(c_topicCode, '^[A-Z][0-9]$') AND NOT REGEXP_LIKE(c_topicCode, '^[IOQNYZ]'))
All that said, I would rather see a table of TopicCodes that is populated with the correct values. Then you can just use a foreign key relationship to define the appropriate codes.
Use the regular expression ^[A-HJ-MPR-X]\d$ to match an upper-case character excluding I,O,Q,N,Y,Z followed by a digit:
CREATE TABLE channels (
id number CONSTRAINT channel__id__pk PRIMARY KEY,
Name varchar(100) CONSTRAINT channel__name__nn NOT NULL,
DateTime date CONSTRAINT channel__date__nn NOT NULL,
UserName varchar(100) CONSTRAINT channel__username__NN NOT NULL
CONSTRAINT channel__username__U UNIQUE,
TopicCode varchar(4),
CONSTRAINT channel__topiccode__chk CHECK ( REGEXP_LIKE( topiccode, '^[A-HJ-MPR-X]\d$' ) )
);
db<>fiddle
Also, you don't need to call the table channeltable just call it channels and you don't need to prefix the column names with the table name and you can name all the constraints (rather than relying on system generated constraint names which makes it much harder to track down issues when you are debugging).
Consider the following check constrait:
create table channelTable (
...
topicCode varchar(4) not null
check(
substr(c_topicCode, 1, 1) not in ('I', 'O', 'Q', 'V', 'Y', 'Z')
and regexp_like(topicCode, '^[A-Z]\d')
),
...
);
The first condition ensures that the code does not start with one of the forbidden characters, the second valides that it stats with an upper alphabetic character, followed by a number.
To avoid using two conditions, an alternative would be to list all allowed characters in the first position:
check(regexp_like(topicCode, '^[ABCDEFGHJKLMNPRSTUVWX]\d'))
This works in Oracle, and in very recent versions of MySQL.
I feel like I am probably missing something really simple, but I really can't figure out what I'm doing wrong. I'm trying to use a check constraint to make sure zipcodes are 5 digit numbers, but the check restraint keeps failing. Here is the table creating with the constraint:
Create Table Students (
StudentID Int Primary Key Identity(1,1)
StudentNumber nVarchar(100) Unique Not Null,
...
StudentZipCode nChar(10) Not Null
)
Go
Alter Table Students Add Constraint chZipCode
CHECK (StudentZipCode LIKE '[0-9][0-9][0-9][0-9][0-9]' OR StudentZipCode
Like '[0-9][0-9][0-9][0-9][0-9]-[0-9][0-9][0-9][0-9]')
Go
Codes like 12345-6789 work, but when I try to insert the values like '12345' or '01234' it gives me this error:
The INSERT statement conflicted with the CHECK constraint "chZipCode". The conflict occurred in database ..., table "dbo.Students", column 'StudentZipCode'.
It fails because you defined the zip code as a char() instead of a varchar(). Hence, it has a bunch of spaces padding it out.
So, define it as:
Create Table Students (
StudentID Int Primary Key Identity(1,1),
StudentNumber nVarchar(100) Unique Not Null,
StudentZipCode nVarChar(10) Not Null,
CHECK (StudentZipCode LIKE '[0-9][0-9][0-9][0-9][0-9]' OR
StudentZipCode LIKE '[0-9][0-9][0-9][0-9][0-9]-[0-9][0-9][0-9][0-9]')
);
Then '12345' works, because it matches the first of the LIKE patterns.
'012344' does not work, because no pattern has six digits in a row.
Here is a SQL Fiddle.
I need to create a table User with telephone_number and e_mail_adress columns. Each row must have at least one of those columns set. It could have both or just one, but it must have at least one of them.
How can I express that constraint in SQL?
create table Users (
/* Whatever */
TelephoneNumber varchar(2000) null,
EmailAddress varchar(5) null,
constraint CK_AtLeastOneContact CHECK (
TelephoneNumber is not null or
EmailAddress is not null
)
)
You may want to adjust the data types :-)