can't create table in mysql because of foriegn key constraint - mysql

Question

i am trying to create the codedata table in mysql but get error #1215 - Cannot add foreign key constraint. can someone please help me figure out what is wrong? thanks in advance for your help!
here is the code that doesn't work:
DROP TABLE IF EXISTS `interviewcodes`.`codedata` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`codedata` (
`StudyID` INT(11) NOT NULL,
`ParticipantID` INT(11) NOT NULL,
`CoderID` INT(11) NOT NULL,
`CodingMonth` INT(11) NOT NULL,
`CodingDay` INT(11) NOT NULL,
`CodingYear` INT(11) NOT NULL,
`StudyQuestionLabel` VARCHAR(45) NOT NULL,
`StudyQuestionResponse` VARCHAR(245) NULL,
`IWAcode` INT(11) NULL DEFAULT 0,
`CQcode` INT(11) NULL DEFAULT 0,
`CRcode` INT(11) NULL DEFAULT 0,
`PMinusCode` INT(11) NULL DEFAULT 0,
`PPlusCode` INT(11) NULL DEFAULT 0,
`PROcode` INT(11) NULL DEFAULT 0,
`CONcode` INT(11) NULL DEFAULT 0,
`RELcode` INT(11) NULL DEFAULT 0,
`NOAcode` INT(11) NULL DEFAULT 0,
`OTHcode` INT(11) NULL DEFAULT 0,
`TotalScore` INT(11) NULL DEFAULT 0,
`Remark` VARCHAR(5000) NULL DEFAULT NULL,
INDEX `fk_CodeData_Participant1_idx` (`ParticipantID` ASC),
INDEX `fk_CodeData_StudyCoders1_idx` (`CoderID` ASC),
INDEX `fk_codedata_studyquestion1_idx` (`StudyQuestionLabel` ASC),
PRIMARY KEY (`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`),
CONSTRAINT `fk_CodeData_Participant1`
FOREIGN KEY (`ParticipantID`)
REFERENCES `interviewcodes`.`participant` (`ParticipantID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_CodeData_StudyCoders1`
FOREIGN KEY (`CoderID`)
REFERENCES `interviewcodes`.`studycoders` (`CoderID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_codedata_studylkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_codedata_studyquestion1`
FOREIGN KEY (`StudyQuestionLabel`)
REFERENCES `interviewcodes`.`studyquestion` (`StudyQuestionLabel`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
here is the code i used to create the other tables, which ran correctly:
DROP TABLE IF EXISTS `interviewcodes`.`interviewerlkup` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`interviewerlkup` (
`InterviewerID` INT(11) NOT NULL AUTO_INCREMENT,
`InterviewerFirstName` VARCHAR(45) NOT NULL,
`InterviewerLastName` VARCHAR(45) NOT NULL,
PRIMARY KEY (`InterviewerID`))
ENGINE = InnoDB
AUTO_INCREMENT = 3
DEFAULT CHARACTER SET = utf8;
DROP TABLE IF EXISTS `interviewcodes`.`studylkup` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`studylkup` (
`StudyID` INT(11) NOT NULL AUTO_INCREMENT,
`StudyName` VARCHAR(45) NOT NULL,
`StudyPIFirstName` VARCHAR(45) NULL,
`StudyPILastName` VARCHAR(45) NULL,
`StudyStartMonth` INT(11) NOT NULL,
`StudyStartDay` INT(11) NOT NULL,
`StudyStartYear` INT(11) NOT NULL,
PRIMARY KEY (`StudyID`))
ENGINE = InnoDB
AUTO_INCREMENT = 4
DEFAULT CHARACTER SET = utf8;
DROP TABLE IF EXISTS `interviewcodes`.`studyinterviewers` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`studyinterviewers` (
`StudyID` INT(11) NOT NULL,
`InterviewerID` INT(11) NOT NULL,
PRIMARY KEY (`StudyID`, `InterviewerID`),
INDEX `fk_StudyInterviewers_InterviewerLkup1_idx` (`InterviewerID` ASC),
CONSTRAINT `fk_StudyInterviewers_InterviewerLkup1`
FOREIGN KEY (`InterviewerID`)
REFERENCES `interviewcodes`.`interviewerlkup` (`InterviewerID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_StudyInterviewers_StudyLkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
DROP TABLE IF EXISTS `interviewcodes`.`participant` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`participant` (
`ParticipantID` INT(11) NOT NULL AUTO_INCREMENT,
`ParticipantCaseID` VARCHAR(45) NOT NULL,
`StudyID` INT(11) NOT NULL,
`InterviewerID` INT(11) NOT NULL,
`InterviewMonth` INT(11) NULL DEFAULT NULL,
`InterviewDay` INT(11) NULL DEFAULT NULL,
`InterviewYear` INT(11) NULL DEFAULT NULL,
PRIMARY KEY (`ParticipantID`),
INDEX `fk_participant_studyinterviewers1_idx` (`InterviewerID` ASC),
CONSTRAINT `fk_participant_studyinterviewers1`
FOREIGN KEY (`InterviewerID`)
REFERENCES `interviewcodes`.`studyinterviewers` (`InterviewerID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_participant_studylkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
AUTO_INCREMENT = 6
DEFAULT CHARACTER SET = utf8;
DROP TABLE IF EXISTS `interviewcodes`.`coderlkup` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`coderlkup` (
`CoderID` INT(11) NOT NULL AUTO_INCREMENT,
`CoderFirstName` VARCHAR(45) NOT NULL,
`CoderLastName` VARCHAR(45) NOT NULL,
PRIMARY KEY (`CoderID`))
ENGINE = InnoDB
AUTO_INCREMENT = 3
DEFAULT CHARACTER SET = utf8;
DROP TABLE IF EXISTS `interviewcodes`.`studycoders` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`studycoders` (
`StudyID` INT(11) NOT NULL,
`CoderID` INT(11) NOT NULL,
PRIMARY KEY (`StudyID`, `CoderID`),
INDEX `fk_StudyCoders_CoderLkup1_idx` (`CoderID` ASC),
CONSTRAINT `fk_StudyCoders_CoderLkup1`
FOREIGN KEY (`CoderID`)
REFERENCES `interviewcodes`.`coderlkup` (`CoderID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_StudyCoders_StudyLkup1`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
DROP TABLE IF EXISTS `interviewcodes`.`studyquestion` ;
CREATE TABLE IF NOT EXISTS `interviewcodes`.`studyquestion` (
`StudyID` INT(11) NOT NULL,
`StudyQuestionLabel` VARCHAR(45) NOT NULL,
PRIMARY KEY (`StudyID`, `StudyQuestionLabel`),
CONSTRAINT `fk_StudyQuestion_StudyLkup`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
here is the last part of my code, after i try to create the codedata table:
SET SQL_MODE=#OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=#OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=#OLD_UNIQUE_CHECKS;
ALTER IGNORE TABLE `StudyLkup` ADD UNIQUE INDEX(`StudyName`);
ALTER IGNORE TABLE `InterviewerLkup` ADD UNIQUE INDEX(`InterviewerFirstName`, `InterviewerLastName`);
ALTER IGNORE TABLE `CoderLkup` ADD UNIQUE INDEX(`CoderFirstName`, `CoderLastName`);
ALTER IGNORE TABLE `Participant` ADD UNIQUE INDEX(`ParticipantCaseID`, `StudyID`);
ALTER IGNORE TABLE `StudyCoders` ADD UNIQUE INDEX(`StudyID`, `CoderID`);
ALTER IGNORE TABLE `StudyInterviewers` ADD UNIQUE INDEX(`StudyID`, `InterviewerID`);
ALTER IGNORE TABLE `StudyQuestion` ADD UNIQUE INDEX(`StudyID`, `StudyQuestionLabel`);
ALTER IGNORE TABLE `CodeData` ADD UNIQUE INDEX(`StudyID`, `ParticipantID`, `CoderID`, `StudyQuestionLabel`);

Answer 1

It will work if you perform this:
CREATE TABLE IF NOT EXISTS `interviewcodes`.`studyquestion` (
`StudyID` INT(11) NOT NULL,
`StudyQuestionLabel` VARCHAR(45) NOT NULL,
PRIMARY KEY (`StudyID`, `StudyQuestionLabel`),
key(`StudyQuestionLabel`), -- <-------- I added this
CONSTRAINT `fk_StudyQuestion_StudyLkup`
FOREIGN KEY (`StudyID`)
REFERENCES `interviewcodes`.`studylkup` (`StudyID`)
ON DELETE NO ACTION
ON UPDATE NO ACTION
)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
Reason: Left-most issue on StudyQuestionLabel is lacking.
Though StudyQuestionLabel is in a composite key it your code, it is not left-most.
Note that I created an interviewcodes schema and tested it.
From the Manual Page Using FOREIGN KEY Constraints a quote:
... In the referencing table, there must be an index where the foreign
key columns are listed as the first columns in the same order.