Class Check

Namespace

YndigoBlue.Velocity.Constraints

Assembly

YndigoBlue.Velocity.dll

Represents a check constraint that enforces domain integrity by limiting the values that can be placed in a column.

public class Check : Constraint, IEquatable<Constraint>, IComparable<Constraint>

Inheritance

object

Constraint

Check

Implements

IEquatable<Constraint>

IComparable<Constraint>

Remarks

Check constraints validate data based on logical expressions. They are evaluated when data is inserted or updated. Common uses include range checks, value lists, and complex business rules.

Examples

using (var manager = new Manager(connection))
{
    var schema = manager.LoadSchema("myschema");
    var table = schema["products"];

    Column colPrice = table["price"];
    Column colStatus = table["status"];
    Column colQuantity = table["quantity"];

    // Simple range check: price must be greater than zero
    Check checkPrice = table.CreateCheckConstraint("ck_products_price", [
        colPrice, new CheckOperator(CheckOperatorType.GreaterThan), new Literal<decimal>(0) ]);

    // String value check: status must not be empty
    Check checkStatus = table.CreateCheckConstraint("ck_products_status", [
        colStatus, new CheckOperator(CheckOperatorType.NotEquals), new Literal<string>("") ]);

    // Compound check: price < 10000 OR quantity < 500
    Check checkCompound = table.CreateCheckConstraint("ck_products_compound", [
        colPrice, new CheckOperator(CheckOperatorType.LessThan), new Literal<decimal>(10000),
        new CheckOperator(CheckOperatorType.Or),
        colQuantity, new CheckOperator(CheckOperatorType.LessThan), new Literal<int>(500) ]);

    // Apply the constraints to the database
    manager.CreateConstraint(checkPrice);
    manager.CreateConstraint(checkStatus);
    manager.CreateConstraint(checkCompound);
}

Properties

CheckItems

Gets or sets the collection of check items that make up the check expression.

ConstraintType

Gets the type of constraint (PrimaryKey, ForeignKey, Unique, Check, or Default).

Definition

Gets or sets the check constraint definition as a string (used when loading from database).

Methods

IsEqual(Constraint)

Always returns true. A check item is usually transformed by an RDBMS and impossible to reliably compare

ToString()

Returns a string that represents the current object.