大约有 3,620 项符合查询结果（耗时：0.0143秒） [XML]
Is Redis just a cache?
...ures are fundamentals of programs, or applications. Consider you are using SQL databases as storage technology and need to construct a list, a hash map, a ranking set or things like that, it's kind of pain in the neck. Redis can provide you these functionalities directly in a very simple way, thus h...
Questions every good Java/Java EE Developer should be able to answer? [closed]
...y there are two Date classes; one in java.util package and another in java.sql?
What happens if an exception is thrown in finally block? Is the remaining finally executed or not?
There is a garbage collector alright, but then is memory leak totally absent in a Java applications? If not, how so?
Fo...
What is Express.js?
...aries such as Mongoose for MongoDB, Sequelize (http://sequelizejs.com) for SQL databases, Waterline (https://github.com/balderdashy/waterline) for many databases into the stack.
Alternatives
Other Node.js frameworks to consider (https://www.quora.com/Node-js/Which-Node-js-framework-is-best-for...
MongoDB relationships: embed or reference?
...y you much) there is no immediate need to normalize data like you would in SQL. In particular any data that is not useful apart from its parent document should be part of the same document.
Separate data that can be referred to from multiple places into its own collection.
This is not so much a "s...
How to find the size of an array in postgresql
...w that the array is 1-dimensional (which is likely) and are running PostgreSQL 9.4 or higher, you can use cardinality:
SELECT cardinality(id) FROM example;
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How to test Spring Data repositories?
...serting object instances through the EntityManager or repo, or via a plain SQL file) and then execute the query methods to verify the outcome of them.
Testing custom implementations
Custom implementation parts of the repository are written in a way that they don't have to know about Spring Data JP...
How to select bottom most rows?
...ere n is the count; x <= n
E.g. Select Bottom 1000 from Employee:
In T-SQL,
DECLARE
@bottom int,
@count int
SET @bottom = 1000
SET @count = (select COUNT(*) from Employee)
select * from Employee emp where emp.EmployeeID not in
(
SELECT TOP (@count-@bottom) Employee.EmployeeID FROM Employee
...
How does Amazon RDS backup/snapshot actually work?
...
We also run several RDS instances, in addition to MySQL on some machines that we manage ourselves. I can't comment specifically, as I'm not an Amazon engineer, but several things I've learned that might explain what you're seeing:
Although Amazon does not share the backend d...
Can someone explain mappedBy in JPA and Hibernate?
...not something you usually want to do and can cause problems with the order SQL statements are executed.
– Affe
Feb 2 '12 at 7:51
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What is copy-on-write?
...used in maintenance of instant snapshot on database servers like Microsoft SQL Server 2005. Instant snapshots preserve a static view of a database by storing a pre-modification copy of data when underlaying data are updated. Instant snapshots are used for testing uses or moment-dependent reports and...