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Questions tagged [check-constraints]

CHECK constraints enforce domain integrity by limiting the values that are accepted by one or more columns.

SQL CHECK constraints enforce domain integrity by limiting the values that are accepted by one or more columns.

You can create a CHECK constraint with any logical (Boolean) expression that returns TRUE or FALSE based on the logical operators. For example, the range of values for a salary column can be limited by creating a CHECK constraint that allows for only data that ranges from $15,000 through $100,000. This prevents salaries from being entered beyond the regular salary range. The logical expression would be the following: salary >= 15000 AND salary <= 100000.

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Hibernate non-negative value constraint

I have the table, the snippet below. package test; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Table; …
sergtk
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How can I create a CHECK constraint on a VARCHAR column in MSSQL specifying a valid set of characters that may appear in the data?

I have a VARCHAR(30) column in a Microsoft SQL database representing a username. I'd like to add a CHECK constraint that allows only a certain range of characters to be used: specifically, a-z, A-Z, underscore and dash. What expression must I use?
Jake Petroules
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MySql workbench CHECK constraint

Here I want to create 2 CHECK constraint before the record insert to the database. ALTER TABLE SubjectEnrollment ADD CONSTRAINT register CHECK (register <= classSize AND register >=0), ADD CONSTRAINT available CHECK (available <= classSize AND…
helloworld1234
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SQL Interview: Prevent overlapping date range

Say there is an appointment_booking table for a list of Managers (or HRs) with startDatetime and endDatetime, then how do one design the table carefully such that it doesn't accept next entry that overlaps for same manager if he/she has appointment…
user2518
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How to check if at least one of two specific fields in a table is NOT NULL in Sqlalchemy ORM?

I have two fields: class Person(base): field1 = Column(String(32), unique=True, nullable=True) field2 = Column(String(128), unique=True, nullable=True) field3 = ... ... I need to create a constraint, to check if at least one of…
Farshid Ashouri
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Does MySQL support check constraint?

Does MySQL support check constraint? I am able to execute the following script in MySQL without error. ALTER TABLE EMP_DB_DESIGN_EXCEL ADD ( CONSTRAINT CHK_EMP_IS_ACTIVE CHECK (IS_ACTIVE IN ('Y','N'))); But it is not reflected if I query: …
Rakesh Goyal
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How to create a CHECK constraint from Mysql Workbench

I want to add a check constraint for example ALTER TABLE fruit ADD CONSTRAINT check_colour CHECK(color IN ('black','white', 'green')) I can do it in the command line, however, I can't find the option to add a check constraint in Mysql Workbench. I…
Joey
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How to enforce a CHECK constraint across multiple tables

I have a database that records breeding information for cows in Microsoft SQL Server 2012 Express. Obviously, a cow cannot be bred until after she is born, and she may be bred multiple times during her life; and I need to enforce these constraints…
Milliron X
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One check constraint or multiple check constraints?

Any suggestions on whether fewer check constraints are better, or more? How should they be grouped if at all? Suppose I have 3 columns which are VARCHAR2(1 BYTE), each of which is a 'T'/'F' flag. I want to add a check constraint to each column…
aw crud
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PostgreSQL Unique Constraint with Exclusions

I have a table: CREATE TABLE dbo."TransportInteraction" ( "Id" bigint NOT NULL DEFAULT nextval('dbo."TransportInteraction_Id_seq"'::regclass), "Message" character varying(256), "TransportActionId" integer NOT NULL, "TimeCreated" timestamp…
Anestis Kivranoglou
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How can I copy records between tables only if they are valid according to check constraints in Firebird/Interbase?

I want to copy a bunch of records from a temp table to a target table. The problem is that some records may violate check constraints in the target table so I want to insert everything that is possible and generate error logs somewhere else for the…
Rafael Piccolo
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Check constraint without columns

Today I found an interesting constraint on one of the tables: alter table T1 add constraint C$T1_DUMMY check (null is null); Any idea why we need this?
turbanoff
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SQL: Check constraint depends on other tables

I have 3 tables: Member, Employer, and Location. Member has MemberID, EmployerID, and LocationID. Employer has EmployerID. Location has EmployerID, LocationID. Member <<---> Employer Location <<---> Employer Member <---> Location I need to make…
mtmurdock
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Make SQL Server use CHECK CONSTRAINT only on inserted or updated rows

I would like to apply a business rule to the rows in a table going forward (SQL Server 2008). However, there is historical data in the table that will not conform to this rule, and there is no good way to make it conform (unknown values with no…
Dave Mateer
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Check Constraints in SQL- Specify a value could be null or a constraint

I am trying to incorporate a check constraint in SQLite where the requirement is the following: The value could be null If the value is not null then it should be greater than 3. So, in my create table I wrote create table T(A real check(A = null…
Vinayak Agarwal
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