Grails Hibernate异常：尝试从null一对一属性中分配id

Question

我试图在两个域之间映射一对一的关系，其中TemplateOutputTransDisplayMap具有来自TemplateOutput的外部PK。当我去保存ToTransDisplayMap的实例时，我收到以下错误：

org.hibernate.id.IdentifierGenerationException 尝试从null一对一属性中分配id [TemplateOutputTransDisplayMap.templateOutput]

两个域的代码都在下面，从TemplateOutputTransDisplayMap开始，然后是TemplateOutput：

class TemplateOutputTransDisplayMap {

static belongsTo = [templateOutput:TemplateOutput, templateStep:TemplateStep]
TemplateOutput templateOutput

Long id
String tsStep
String toParameterName
String displayLabel
String defaultValue
String toMapParameter
String sqlQuery
String selectClause
String whereClause
Long   fetchCount
String transTable
String columnName
String displayed
String xPath
String isNameValue

static mapping = {

    table 'TO_TRANS_DISP_MAP'
    version false

    id              column: 'TO_SYSID', generator: 'foreign', params:      [property:'templateOutput']

    templateOutput  column: 'TO_SYSID', insertable: false, updateable: false
    templateStep    column: 'TO_TS_SYSID'
    tsStep          column: 'TS_STEP'
    toParameterName column: 'TO_PARAM_NAME'
    displayLabel    column: 'DISPLAY_LABEL'
    defaultValue    column: 'DEFAULT_VALUE'
    toMapParameter  column: 'TO_MAP_PARAM'
    sqlQuery        column: 'SQL_QUERY'
    selectClause    column: 'SELECT_CLAUSE'
    whereClause     column: 'WHERE_CLAUSE'
    fetchCount      column: 'FETCH_COUNT'
    transTable      column: 'TRANS_TABLE'
    columnName      column: 'COLUMN_NAME'
    xPath           column: 'XPATH'
    isNameValue     column: 'IS_NAME_VALUE'

}

static constraints = {
    tsStep          (maxSize:250,  blank:true, nullable:true)
    toParameterName (maxSize:250,  blank:true, nullable:true)
    displayLabel    (maxSize:250,  blank:true, nullable:true)
    defaultValue    (maxSize:250,  blank:true, nullable:true)
    toMapParameter  (maxSize:250,  blank:true, nullable:true)
    sqlQuery        (maxSize:1000, blank:true, nullable:true)
    selectClause    (maxSize:100,  blank:true, nullable:true)
    whereClause     (maxSize:1000, blank:true, nullable:true)
    fetchCount      (maxSize:3,    blank:true, nullable:true)
    transTable      (maxSize:250,  blank:true, nullable:true)
    columnName      (maxSize:30,   blank:true, nullable:true)
    displayed       (maxSize:1,    blank:true, nullable:true)
    xPath           (maxSize:2000, blank:true, nullable:true)
    isNameValue     (maxSize:3,    blank:true, nullable:true)
    templateStep                  (blank:true, nullable:true)
   }
}




class TemplateOutput {

static belongsTo = [templateStep:TemplateStep]
static hasOne = [templateOutputTransDisplayMap:TemplateOutputTransDisplayMap]

Long id
String parameterName
String usage
String mappingParameter 

static mapping = {

    table 'TEMPLATE_OUTPUT'
    version false

    id               column: 'SYSID', generator: 'assigned'
    templateStep     column: 'TS_SYSID'
    parameterName    column: 'PARAMETER_NAME'
    mappingParameter column: 'MAPPING_PARAMETER'

}

static constraints = {
    parameterName    (maxSize:250, blank:true, nullable:true)
    usage            (maxSize:250, blank:true, nullable:true)
    mappingParameter (maxSize:250, blank:true, nullable:true)
    templateStep                  (blank:true, nullable:true)
    templateOutputTransDisplayMap (blank:true, nullable:true)
    }
}

任何帮助都将不胜感激。