Class CheckOperator

Namespace: YndigoBlue.Velocity.Model

Assembly: YndigoBlue.Velocity.dll

Represents a comparison operator used in CHECK constraints to validate column values.

public class CheckOperator : ICheckItem

Inheritance: object

CheckOperator

Implements: ICheckItem

Examples

Simple CHECK constraint with greater than:

// Ensure age is at least 18
Table usersTable = schema.CreateTable("users");
Column ageColumn = usersTable.AddColumn("age", DataType.Integer);

CheckConstraint ageCheck = new CheckConstraint("age_minimum");
ageCheck.Add(ageColumn);
ageCheck.Add(new CheckOperator(CheckOperatorType.GreaterThanOrEquals));
ageCheck.Add(new Literal<int>(18));

usersTable.AddCheckConstraint(ageCheck);
// SQL: ALTER TABLE users ADD CONSTRAINT age_minimum CHECK (age >= 18)

Range validation with multiple operators:

// Ensure age is between 18 and 120
CheckConstraint ageRange = new CheckConstraint("age_range");
ageRange.Add(ageColumn);
ageRange.Add(new CheckOperator(CheckOperatorType.GreaterThanOrEquals));
ageRange.Add(new Literal<int>(18));
ageRange.Add(new BooleanItem(BooleanType.And));
ageRange.Add(ageColumn);
ageRange.Add(new CheckOperator(CheckOperatorType.LessThanOrEquals));
ageRange.Add(new Literal<int>(120));

usersTable.AddCheckConstraint(ageRange);
// SQL: CHECK (age >= 18 AND age <= 120)

Positive value validation:

// Ensure price is greater than zero
Table productsTable = schema.CreateTable("products");
Column priceColumn = productsTable.AddColumn("price", DataType.Decimal, precision: 10, scale: 2);

CheckConstraint positivePrice = new CheckConstraint("positive_price");
positivePrice.Add(priceColumn);
positivePrice.Add(new CheckOperator(CheckOperatorType.GreaterThan));
positivePrice.Add(new Literal<decimal>(0m));

productsTable.AddCheckConstraint(positivePrice);
// SQL: CHECK (price > 0)

Not equals validation:

// Ensure status is not 'deleted'
Column statusColumn = usersTable.AddColumn("status", DataType.VarChar, size: 50);

CheckConstraint notDeleted = new CheckConstraint("not_deleted");
notDeleted.Add(statusColumn);
notDeleted.Add(new CheckOperator(CheckOperatorType.NotEquals));
notDeleted.Add(new Literal<string>("deleted"));

usersTable.AddCheckConstraint(notDeleted);
// SQL: CHECK (status != 'deleted')

Remarks

CheckOperator is used within CHECK constraints to define validation rules for table columns. These operators compare column values against literal values to ensure data integrity. Supported comparison operators include:

Equals (=)Value must equal the specified value
NotEquals (!=, <>)Value must not equal the specified value
GreaterThan (>)Value must be greater than the specified value
LessThan (<)Value must be less than the specified value
GreaterThanOrEquals (>=)Value must be greater than or equal to the specified value
LessThanOrEquals (<=)Value must be less than or equal to the specified value

Constructors

CheckOperator(CheckOperatorType): Creates a new check operator for use in CHECK constraints.

Properties

CheckConstraintType: Gets the check constraint type (always CheckConstraintType.Operator).

CheckOperatorType: Gets or sets the type of comparison operator used in the CHECK constraint.

Methods

IsEqual(ICheckItem): Determines whether this check operator is equal to another check item.