大约有 37,000 项符合查询结果（耗时：0.0258秒） [XML]
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
...ysql.server stop
Start it in safe mode:
$ sudo mysqld_safe --skip-grant-tables --skip-networking
(above line is the whole command)
This will be an ongoing command until the process is finished so open another shell/terminal window, log in without a password:
$ mysql -u root
mysql> UPDATE ...
Why was the switch statement designed to need a break?
...c is just a clean interface to standard assembly idioms. When writing jump table driven flow control, the programmer has the choice of falling through or jumping out of the "control structure", and a jump out requires an explicit instruction.
So, c does the same thing...
...
How to check if a variable is set in Bash?
... This answer is very confusing. Any practical examples on how to use this table?
– Ben Davis
Sep 27 '14 at 17:16
13
...
Java: parse int value from a char
...ou take '2' - '0' you really just get 50 - 48 = 2. Have a look at an ASCII table in order to understand this principle better. Also, 'x' means get the ascii value of the character in Java.
– Kevin Van Ryckegem
May 13 '17 at 13:16
...
Rails 3 migrations: Adding reference column?
...class AddUserToTester < ActiveRecord::Migration
def change
change_table :testers do |t|
t.references :user, index: true
end
end
def down
change_table :testers do |t|
t.remove :user_id
end
end
end
c.f.: http://apidock.com/rails/ActiveRecord/ConnectionAdapters...
How can I read and parse CSV files in C++?
...::istream &in) {
std::vector<std::vector<std::string>> table;
std::string row;
while (!in.eof()) {
std::getline(in, row);
if (in.bad() || in.fail()) {
break;
}
auto fields = readCSVRow(row);
table.push_back(fields);
...
Versioning SQL Server database
...N to N+1. (These go in your version control system.) A _version_history_ table, something like
create table VersionHistory (
Version int primary key,
UpgradeStart datetime not null,
UpgradeEnd datetime
);
gets a new entry every time an upgrade script runs which corresponds to th...
ActiveRecord: size vs count
...e way to go if you are using the data.
Example: Summary of a fully loaded table, titles of displayed data, etc.
size
It checks if the data was loaded (i.e. already in rails) if so, then just count it, otherwise it calls count. (plus the pitfalls, already mentioned in other entries).
def size
l...
How to return an empty ActiveRecord relation?
...
A more portable solution that doesn't require an "id" column and doesn't assume there won't be a row with an id of 0:
scope :none, where("1 = 0")
I'm still looking for a more "correct" way.
...
LEFT OUTER joins in Rails 3
... the :include option, which will perform an
INNER JOIN on the associated table(s), or an array containing a
mixture of both strings and named associations.
If the value is a
string, then the records will be returned read-only since they will
have attributes that do not correspond to th...