* Added the Unique validator thanks to @elpete!

Author: lmajano

changelog.md

@@ -3,6 +3,7 @@
 ## 2.0.1
 
 * Updated `RequiredUnless` and `RequiredIf` to use struct literal notation instead of the weird parsing we did.
+* Added the `Unique` validator thanks to @elpete!
 
 ## 2.0.0
 

models/validators/AcceptedValidator.cfc

@@ -18,11 +18,12 @@ component accessors="true" singleton {
 
 	/**
 	 * Will check if an incoming value validates
-	 * @validationResultThe result object of the validation
-	 * @targetThe target object to validate on
-	 * @fieldThe field on the target object to validate on
-	 * @targetValueThe target value to validate
-	 * @validationDataThe validation data the validator was created with
+	 *
+	 * @validationResult The result object of the validation
+	 * @target The target object to validate on
+	 * @field The field on the target object to validate on
+	 * @targetValue The target value to validate
+	 * @validationData The validation data the validator was created with
 	 */
 	boolean function validate(
 		required any validationResult,

models/validators/UniqueValidator.cfc

@@ -0,0 +1,70 @@
+/**
+ * Copyright since 2020 by Ortus Solutions, Corp
+ * www.ortussolutions.com
+ * ---
+ * This validator checks the database according to validation data for field uniqueness
+ * - table : The table name to seek
+ * - column : The column to evaluate for uniqueness or defaults to the name of the field
+ */
+component accessors="true" singleton {
+
+	property name="name";
+
+	/**
+	 * Constructor
+	 */
+	UniqueValidator function init(){
+		variables.name = "Unique";
+		return this;
+	}
+
+	/**
+	 * Will check if an incoming value validates
+	 *
+	 * @validationResult The result object of the validation
+	 * @target The target object to validate on
+	 * @field The field on the target object to validate on
+	 * @targetValue The target value to validate
+	 * @validationData The validation data the validator was created with
+	 */
+	boolean function validate(
+		required any validationResult,
+		required any target,
+		required string field,
+		any targetValue,
+		any validationData
+	){
+		// Default the target column
+		var targetColumn = ( isNull( arguments.validationData.column ) ? arguments.field : arguments.validationData.column );
+		// Query it
+		var exists = queryExecute(
+			"SELECT 1 FROM #arguments.validationData.table# WHERE #targetColumn# = ?",
+			[ arguments.targetValue ]
+		).recordCount > 0;
+
+		if ( !exists ) {
+			return true;
+		}
+
+		validationResult.addError(
+			validationResult.newError(
+				argumentCollection = {
+					message : "The #targetColumn# '#arguments.targetValue#' is already in use",
+					field : arguments.field,
+					validationType : getName(),
+					validationData : arguments.validationData
+				}
+			)
+		);
+
+		return false;
+	}
+
+	/**
+	 * Get the name of the validator
+	 */
+	string function getName(){
+		return "Unique";
+	}
+
+}

readme.md

@@ -153,6 +153,12 @@ this.constraints = {
 
 		// UDF to use for validation, must return boolean accept the incoming value and target object, validate(value,target):boolean
 		udf = variables.UDF or this.UDF or a closure.
+
+		// Check if a column is unique in the database
+		unique = {
+			table : The table name,
+			column : The column to check, defaults to the property field in check
+		}
 
 		// Custom validator, must implement coldbox.system.validation.validators.IValidator
 		validator : path or wirebox id, example: 'mypath.MyValidator' or 'id:MyValidator'