mysql - Delete row from table with conditions uniqueField = 1 -

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  तालिका से हटाएं WHERE uniqueField = 1   
 जब MySQL को पंक्ति मिलती है  uniqueField = 1  के साथ, यह इसे हटा देगा। फिर अन्य पंक्तियों को रोकना बंद कर देता है, क्योंकि एक विशिष्ट फ़ील्ड में केवल  <0>        > UniqueField = 1 ?   
 
 
 यदि  uniqueField  घोषित किया गया है < कोड> अनोखा , अनन्य बाध्यता को पुलिस के लिए एक निहित सूचकांक बनाया जाता है।  
  MySQL  सबसे अधिक संभवतः रिकॉर्ड को हटाने के लिए इस अनुक्रमणिका का उपयोग करेगा।  
 यह सूचकांक  UNIQUE  होगा, इंजन केवल एक रिकॉर्ड को स्कैन करेगा।  
 यदि फ़ील्ड को अनन्य घोषित नहीं किया गया है और अनुक्रमित नहीं किया गया है, तो  MySQL < / कोड> इस फ़ील्ड के मूल्य की जांच के लिए सभी अभिलेखों को स्कैन करना होगा।

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