لو عايزين مثلا نجمع القيم الى شبه بعض فى صفوف مثلا زى ان احنا نعرف عدد العملاء الى عندنا فى كل بلد
لو بصينا على الجدولين الى قدامنا هنلاقى ان فى عمود مشترك ما بينهم و هو customerID و ده خلا ان بقا فى علاقة ما بين الجدولين دول
ال join بتعرضلنا القيم المشتركة ما بين جدولين عن طريق اننا بنحدد العمود المشترك ما بين الجدولين
بعد كده هنعمل import لملف ال csv بتاعنا الى عايزين نحوله ل database
.import favourites.csv favourites
.import favourites.csv favourites
ال command ده بيخيلنا نعرف البنية بتاعت الداتا بيز بتاعتنا و الجداول و الأعمدة الى بتتكون منها
ال primary key بيبقا زى المعرف او القيمة المميزة الى بتميز كل جدول و كل جدول بيبقا ليه primary key واحد بس
Modern Operating Systems 4th Edition--Andrew Tanenbaum.pdf
6.3 MB
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run. If the process is not prepared to handle a signal, then its arrival kills the proc ess (hence the name of the call).
POSIX defines a number of procedures for dealing with time. For example,
time just returns the current time in seconds, with 0 corresponding to Jan. 1, 1970
at midnight (just as the day was starting, not ending). On computers using 32-bit
words, the maximum value time can return is 232 − 1 seconds (assuming an unsign ed integer is used). This value corresponds to a little over 136 years. Thus in the
year 2106, 32-bit UNIX systems will go berserk, not unlike the famous Y2K prob lem that would have wreaked havoc with the world’s computers in 2000, were it
not for the massive effort the IT industry put into fixing the problem. If you cur rently have a 32-bit UNIX system, you are advised to trade it in for a 64-bit one
sometime before the year 2106.
POSIX defines a number of procedures for dealing with time. For example,
time just returns the current time in seconds, with 0 corresponding to Jan. 1, 1970
at midnight (just as the day was starting, not ending). On computers using 32-bit
words, the maximum value time can return is 232 − 1 seconds (assuming an unsign ed integer is used). This value corresponds to a little over 136 years. Thus in the
year 2106, 32-bit UNIX systems will go berserk, not unlike the famous Y2K prob lem that would have wreaked havoc with the world’s computers in 2000, were it
not for the massive effort the IT industry put into fixing the problem. If you cur rently have a 32-bit UNIX system, you are advised to trade it in for a 64-bit one
sometime before the year 2106.