CODEWITHSUNDEEP
mysqlgrailsentity
user2483213
user2483213

Reputation: 331

Grails entity change my tables and create new

I have 2 tables, with relation one to many.

I create 2 entity's on this tables. But when I try get data created third table and in exist tables add new fields.

My tables 

CREATE TABLE `question` (
    `ID` INT(11) NOT NULL AUTO_INCREMENT,
    `Question` VARCHAR(200) NOT NULL,
    PRIMARY KEY (`ID`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB;


CREATE TABLE `answer` (
    `ID` INT(10) NOT NULL AUTO_INCREMENT,
    `QuestionID` INT(11) NOT NULL,
    `Answer` VARCHAR(50) NOT NULL,
    `IsCorrect` TINYINT(1) NULL DEFAULT '0',
    PRIMARY KEY (`ID`),
    INDEX `FK_Question` (`QuestionID`),
    CONSTRAINT `FK_Question` FOREIGN KEY (`QuestionID`) REFERENCES `question` (`ID`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB;

My entity's

class Answer {

    int id

    String answer

    boolean isCorrect
    static belongsTo = Question

    static constraints = {
    }

}

class Question {

    int id
    String question
    List<Answer> answers
    static hasMany = [answers : Answer]

    static constraints = {
    }
}

After using grails, change in mysql tables

CREATE TABLE `question` (
    `ID` INT(11) NOT NULL AUTO_INCREMENT,
    `Question` VARCHAR(200) NOT NULL,
    `version` BIGINT(20) NOT NULL,
    PRIMARY KEY (`ID`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=15;

CREATE TABLE `answer` (
    `ID` INT(10) NOT NULL AUTO_INCREMENT,
    `QuestionID` INT(11) NOT NULL,
    `Answer` VARCHAR(50) NOT NULL,
    `IsCorrect` TINYINT(1) NULL DEFAULT '0',
    `version` BIGINT(20) NOT NULL,
    `is_correct` BIT(1) NOT NULL,
    PRIMARY KEY (`ID`),
    INDEX `FK_Question` (`QuestionID`),
    CONSTRAINT `FK_Question` FOREIGN KEY (`QuestionID`) REFERENCES `question` (`ID`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=32;

CREATE TABLE `question_answer` (
    `question_answers_id` INT(11) NULL DEFAULT NULL,
    `answer_id` INT(11) NULL DEFAULT NULL,
    `answers_idx` INT(11) NULL DEFAULT NULL,
    INDEX `FK561DF237111171E9` (`answer_id`),
    CONSTRAINT `FK561DF237111171E9` FOREIGN KEY (`answer_id`) REFERENCES `answer` (`ID`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB;

So, how fix this problem? Why grails change my tables?

Upvotes: 0

Views: 185

Answers (1)

user800014
user800014

Reputation:

The problem is that you declared:

static belongsTo = Question

But this makes the relation unidirectional, since you cannot query this belongsTo. In this case Grails will use a join table. If you don't want the join table, you need to make it bidirectional, by declaring:

static belongsTo = [question: Question]

More information about this here.

Upvotes: 1

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