大约有 43,000 项符合查询结果（耗时：0.0276秒） [XML]
When to use single quotes, double quotes, and backticks in MySQL
...
Backticks are to be used for table and column identifiers, but are only necessary when the identifier is a MySQL reserved keyword, or when the identifier contains whitespace characters or characters beyond a limited set (see below) It is often recommended to avoid using ...
How to create composite primary key in SQL Server 2008
...
CREATE TABLE UserGroup
(
[User_Id] INT NOT NULL,
[Group_Id] INT NOT NULL
CONSTRAINT PK_UserGroup PRIMARY KEY NONCLUSTERED ([User_Id], [Group_Id])
)
share
|
...
T-SQL stored procedure that accepts multiple Id values
Is there a graceful way to handle passing a list of ids as a parameter to a stored procedure?
6 Answers
...
Chrome ignores autocomplete=“off”
...seems now Chrome ignores the style="display: none;" or style="visibility: hidden; attributes.
You can change it to something like:
<input style="opacity: 0;position: absolute;">
<input type="password" style="opacity: 0;position: absolute;">
In my experience, Chrome only autocompletes...
.Contains() on a list of custom class objects
...
You need to implement IEquatable or override Equals() and GetHashCode()
For example:
public class CartProduct : IEquatable<CartProduct>
{
public Int32 ID;
public String Name;
public Int32 Number;
public Decimal CurrentPrice;
public CartP...
Drop a temporary table if it exists
... IF EXISTS ##CLIENTS_KEYWORD
On previous versions you can use
IF OBJECT_ID('tempdb..##CLIENTS_KEYWORD', 'U') IS NOT NULL
/*Then it exists*/
DROP TABLE ##CLIENTS_KEYWORD
CREATE TABLE ##CLIENTS_KEYWORD
(
client_id INT
)
You could also consider truncating the table instead rather than dropping ...
How to include “zero” / “0” results in COUNT aggregate?
... (and you need to use person as the "driving" table)
SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM person
LEFT JOIN appointment ON person.person_id = appointment.person_id
GROUP BY person.person_id;
The reason why this is working, is that the outer (lef...
How to determine if a record is just created or updated in after_save
...king to use this for an after_save callback.
A simpler solution is to use id_changed? (since it won't change on update) or even created_at_changed? if timestamp columns are present.
Update: As @mitsy points out, if this check is needed outside of callbacks then use id_previously_changed?. See docs...
Hibernate, @SequenceGenerator and allocationSize
...y 50 (default allocationSize value) - and then uses this value as entity ID.
6 Answers
...
Comparing mongoose _id and strings
...
Mongoose uses the mongodb-native driver, which uses the custom ObjectID type. You can compare ObjectIDs with the .equals() method. With your example, results.userId.equals(AnotherMongoDocument._id). The ObjectID type also has a toString() method, if you wish to store a stringified version of t...