Class Literal<T>

Namespace: YndigoBlue.Velocity.Model

Assembly: YndigoBlue.Velocity.dll

Represents a literal constant value used in queries, expressions, and constraints.

public class Literal<T> : ILiteral, IElement, ICheckItem, IDefaultItem

Type Parameters

T: The C# type of the literal value. Common types include: string, int, long, decimal, DateTime, bool, byte[], and others.

Inheritance: object

Literal<T>

Implements: ILiteral

IElement

ICheckItem

IDefaultItem

Examples

Using literals in expressions:

// Calculate: price * 1.1 (add 10% markup)
Expression markupExpression = new Expression("markup_price");
markupExpression.Add(productsTable["price"]);
markupExpression.Add(new ArithmeticOperator(ArithmeticType.Multiply));
markupExpression.Add(new Literal<decimal>(1.1m));

query.AddSelectItem(markupExpression);
// SQL: SELECT price * 1.1 AS markup_price

Using literals with functions:

// ROUND(price * 1.1, 2)
Function roundFunction = new Function(FunctionType.Round);
roundFunction.Add(productsTable["price"]);
roundFunction.Add(new ArithmeticOperator(ArithmeticType.Multiply));
roundFunction.Add(new Literal<decimal>(1.1m));
roundFunction.Add(new Literal<int>(2)); // decimal places

query.AddSelectItem(roundFunction);

Using literals in CHECK constraints:

// Ensure age is between 18 and 120
Table usersTable = schema.CreateTable("users");
Column ageColumn = usersTable.AddColumn("age", DataType.Integer);

CheckConstraint ageCheck = new CheckConstraint("age_check");
ageCheck.Add(ageColumn);
ageCheck.Add(new CheckOperator(CheckOperatorType.GreaterThanOrEquals));
ageCheck.Add(new Literal<int>(18));
ageCheck.Add(new BooleanItem(BooleanType.And));
ageCheck.Add(ageColumn);
ageCheck.Add(new CheckOperator(CheckOperatorType.LessThanOrEquals));
ageCheck.Add(new Literal<int>(120));

usersTable.AddCheckConstraint(ageCheck);

Using literals in DEFAULT constraints:

// Default status to 'pending'
Column statusColumn = usersTable.AddColumn("status", DataType.VarChar, size: 50);
DefaultConstraint defaultStatus = new DefaultConstraint(
    "default_status",
    new Literal<string>("pending")
);
statusColumn.SetDefaultConstraint(defaultStatus);

Remarks

Literal values are type-safe wrappers around constant values that can be used in:

Expression - For arithmetic calculations
Function - As arguments to database functions
CHECK constraints - For validation rules
DEFAULT constraints - For default column values

Each literal automatically generates a unique parameter name for safe SQL generation and tracks metadata like length (for strings) and precision/scale (for decimals).

Constructors

Literal(T): Creates a new literal value.

Properties

CheckConstraintType: Gets the type of check constraint element.

DataType: Gets the database data type of this literal.

DefaultConstraintType: Gets the type of default constraint element.

Length: Gets the length of the literal value (for string types).

ParameterName: Gets the unique parameter name used for this literal in SQL generation.

Precision: Gets the precision of the literal value (for decimal types).

Scale: Gets the scale of the literal value (for decimal types).

Value: Gets the literal's constant value.

Methods

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

IsEqual(IDefaultItem): Determines whether this default item is equal to another default item.

ToString(): Returns a string that represents the current object.