DTD bilan tanishuv
DTD nima?
DTD — bu hujjat tipi ta’rifi (Document Type Definition).
DTD XML hujjatning tuzilmasini hamda ruxsat etilgan elementlar va atributlarini belgilaydi.
Nega DTD’dan foydalanish kerak?
DTD yordamida mustaqil guruhlar ma’lumot almashish uchun standart DTD bo‘yicha kelishib olishlari mumkin.
Ilova XML ma’lumotlari yaroqli (valid) ekanini tekshirish uchun DTD’dan foydalanishi mumkin.
Ichki DTD e’loni
Agar DTD XML fayl ichida e’lon qilinsa, u <!DOCTYPE> ta’rifi ichiga o‘ralishi kerak:
Ichki DTD’ga ega XML hujjat
<?xml version="1.0"?>
<!DOCTYPE note [
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>
]>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend</body>
</note>
XML faylni ko‘rish »
DTD’ni ko‘rish uchun XML faylda "view source" (manbani ko‘rish) bandini tanlang.
Yuqoridagi DTD quyidagicha talqin qilinadi:
- !DOCTYPE note bu hujjatning ildiz elementi note ekanini belgilaydi
- !ELEMENT note note elementi to‘rtta elementni o‘z ichiga olishi kerakligini belgilaydi: "to,from,heading,body"
- !ELEMENT to to elementini "#PCDATA" tipida deb belgilaydi
- !ELEMENT from from elementini "#PCDATA" tipida deb belgilaydi
- !ELEMENT heading heading elementini "#PCDATA" tipida deb belgilaydi
- !ELEMENT body body elementini "#PCDATA" tipida deb belgilaydi
Tashqi DTD e’loni
Agar DTD tashqi faylda e’lon qilinsa, <!DOCTYPE> ta’rifi DTD fayliga havolani o‘z ichiga olishi kerak:
Tashqi DTD’ga havolasi bor XML hujjat
<?xml version="1.0"?>
<!DOCTYPE note SYSTEM "note.dtd">
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
XML faylni ko‘rish »
Va mana DTD’ni o‘z ichiga olgan "note.dtd" fayli:
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>W3Schools Pathfinder
Yutuqlaringizni kuzating – bu bepul!