Q on adding new column# Database - 数据库
g*y
1 楼
Just a thought question: could adding new column crash the program that is
using the table?
using the table?
b*e
2 楼
depending on how the program was written.
If somebody write "insert table t1 values ('xx','xx'...)" without specifying
the column names, then the program will get crashed.
【在 g***y 的大作中提到】
: Just a thought question: could adding new column crash the program that is
: using the table?
If somebody write "insert table t1 values ('xx','xx'...)" without specifying
the column names, then the program will get crashed.
【在 g***y 的大作中提到】
: Just a thought question: could adding new column crash the program that is
: using the table?
y*n
3 楼
I am not sure how a commercial DB is really implemented, but my feeling is
that if a new column is added to the table, the program should get exclusive
lock on the table first and after it gets the lock, it can proceed with adding
new column, right? If so, then existing operations will not be affected
because they will either have IS or IX or S or X lock on the table and all of
them are incompatible with xlock. The program that trys to add new column will
be blocked till all existing program fin
【在 b*e 的大作中提到】
: depending on how the program was written.
: If somebody write "insert table t1 values ('xx','xx'...)" without specifying
: the column names, then the program will get crashed.
that if a new column is added to the table, the program should get exclusive
lock on the table first and after it gets the lock, it can proceed with adding
new column, right? If so, then existing operations will not be affected
because they will either have IS or IX or S or X lock on the table and all of
them are incompatible with xlock. The program that trys to add new column will
be blocked till all existing program fin
【在 b*e 的大作中提到】
: depending on how the program was written.
: If somebody write "insert table t1 values ('xx','xx'...)" without specifying
: the column names, then the program will get crashed.
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