在Django中區分null=True，space=True在Django中添加數據庫字段時，通常會編寫models.CharField(max_length=100, null=True, blank=True)..同樣的事情也發生在ForeignKey, DecimalField有什么基本的區別null=True只blank=True只null=True, blank=True就不同的(CharField, ForeignKey, ManyToManyField, DateTimeField)田野。使用1/2/3的優點/缺點是什么？
3 回答
偶然的你
TA貢獻1841條經驗 獲得超3個贊
null=TrueNULLNOT NULLDateTimeFieldForeignKeyNULL
blank=Trueblank=TrueFalse
NULLCharFieldTextFieldNULL'').
models.DateTimeField(blank=True) # raises IntegrityError if blankmodels.DateTimeField(null=True) # NULL allowed, but must be filled out in a form
null=True, blank=False
models.CharField(blank=True) # No problem, blank is stored as ''models.CharField(null=True) # NULL allowed, but will never be set as NULL
CHARTEXTNULLnull=TrueNoneNULLnull=True.
慕田峪9158850
TA貢獻1794條經驗 獲得超7個贊
blank & null
class Test(models.Model): charNull = models.CharField(max_length=10, null=True) charBlank = models.CharField(max_length=10, blank=True) charNullBlank = models.CharField(max_length=10, null=True, blank=True) intNull = models.IntegerField(null=True) intBlank = models.IntegerField(blank=True) intNullBlank = models.IntegerField(null=True, blank=True) dateNull = models.DateTimeField(null=True) dateBlank = models.DateTimeField(blank=True) dateNullBlank = models.DateTimeField(null=True, blank=True)
CREATE TABLE Test ( id serial NOT NULL, "charNull" character varying(10), "charBlank" character varying(10) NOT NULL, "charNullBlank" character varying(10), "intNull" integer, "intBlank" integer NOT NULL, "intNullBlank" integer, "dateNull" timestamp with time zone, "dateBlank" timestamp with time zone NOT NULL, "dateNullBlank" timestamp with time zone, CONSTRAINT Test_pkey PRIMARY KEY (id))
CREATE TABLE Test ( `id` INT(11) NOT NULL AUTO_INCREMENT, `charNull` VARCHAR(10) NULL DEFAULT NULL, `charBlank` VARCHAR(10) NOT NULL, `charNullBlank` VARCHAR(10) NULL DEFAULT NULL, `intNull` INT(11) NULL DEFAULT NULL, `intBlank` INT(11) NOT NULL, `intNullBlank` INT(11) NULL DEFAULT NULL, `dateNull` DATETIME NULL DEFAULT NULL, `dateBlank` DATETIME NOT NULL, `dateNullBlank` DATETIME NULL DEFAULT NULL)
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