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>

Examples

// Define a table with check constraints
var table = new Table(schema, "products");
table.AddColumn("id", DataType.Integer, autoIncrement: true);
table.AddColumn("name", DataType.VarChar, 100);
table.AddColumn("price", DataType.Decimal);
table.AddColumn("quantity", DataType.Integer);
table.AddColumn("status", DataType.VarChar, 20);

// Create check constraint ensuring price is positive
var checkPrice = new Check("ck_products_price", schema.Name, "products",
    new ICheckItem[] {
        table["price"],
        new CheckOperator(CheckOperatorType.GreaterThan),
        new Literal<decimal>(0)
    });

// Create check constraint for valid status values
var checkStatus = new Check("ck_products_status", schema.Name, "products",
    new ICheckItem[] {
        table["status"],
        new CheckOperator(CheckOperatorType.In),
        new Literal<string>("Active,Inactive,Discontinued")
    });

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.

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

GetColumnsForComparison()

Gets columns for comparison in a name-neutral way. Override in subclasses that have columns.

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.