Conditional constraint in Table

CREATE TABLE SECTION(
    c# int FOREIGN KEY REFERENCES Course(c#),
    se# int,
    emp# int FOREIGN KEY REFERENCES Professor(EMP#),
    class_time time,
    controlNumber int DEFAULT 20,
    CONSTRAINT pk_SectionID PRIMARY KEY (c#, se#),
    
    -----Adding Conditional constraint here ---
    CONSTRAINT chk_controlNumber CHECK (
      controlNumber between 40 AND 60 and (c# < 3000 or c# > 5000) or
      (c# between 3000 and 5000 and controlNumber <= 40))
      
----Remove constraint 
ALTER TABLE TableName
DROP CONSTRAINT constraintName; 

---- Add UNIQUE constraint
ALTER TABLE Persons
ADD CONSTRAINT UC_Person UNIQUE (ID,LastName);

 --//Example:
ALTER TABLE PurchaseOrderChild_UnlockHistory
ADD CONSTRAINT UK_PurOrderChild_UnlockHistory UNIQUE (
[PurOrderMasterID] ASC,	[PurReqMasterID] ASC,
	[ItemID] ASC,	[Version] ASC
);

Conditional constraint using FUNCTION

--- Conditional constraint using FUNCTION
CREATE FUNCTION CheckActiveCount(
  @Id INT
) RETURNS INT 
AS 
BEGIN
 
  DECLARE @ret INT;
  SELECT @ret = COUNT(*) FROM CheckConstraint WHERE Id = @Id AND RecordStatus = 1;
  RETURN @ret;
 
END;
GO
--- Add Constraint using function
ALTER TABLE CheckConstraint
  ADD CONSTRAINT CheckActiveCountConstraint CHECK (NOT (dbo.CheckActiveCount(Id) > 1 AND RecordStatus = 1));
 
 
----Remove constraint 
ALTER TABLE TableName
DROP CONSTRAINT constraintName;