大约有 5,880 项符合查询结果（耗时：0.0324秒） [XML]
How to store a list in a column of a database table
...hrdad's answer to a related question , I get it that a "proper" database table column doesn't store a list. Rather, you should create another table that effectively holds the elements of said list and then link to it directly or through a junction table. However, the type of list I want to creat...
Can I split an already split hunk with git?
...nt to replace the - with a space at the beginning of these lines:
-
-form.table-form #field_teacher + label,
-form.table-form #field_producer_distributor + label {
... and delete the the following line, i.e. the one that begins with +. If you then save and exit your editor, just the removal of t...
How do I escape a reserved word in Oracle?
In TSQL I could use something like Select [table] from tablename to select a column named "table".
5 Answers
...
Why is the order in dictionaries and sets arbitrary?
...lues.
Keys are hashed, and hash values are assigned to slots in a dynamic table (it can grow or shrink based on needs). And that mapping process can lead to collisions, meaning that a key will have to be slotted in a next slot based on what is already there.
Listing the contents loops over the slo...
ROW_NUMBER() in MySQL
... kind of isn't).
I often plump for a null-self-join:
SELECT t0.col3
FROM table AS t0
LEFT JOIN table AS t1 ON t0.col1=t1.col1 AND t0.col2=t1.col2 AND t1.col3>t0.col3
WHERE t1.col1 IS NULL;
“Get the rows in the table for which no other row with matching col1,col2 has a higher col3.” (You w...
How do HashTables deal with collisions?
I've heard in my degree classes that a HashTable will place a new entry into the 'next available' bucket if the new Key entry collides with another.
...
Best practices for in-app database migration for Sqlite
...anges aren't committed.
For making schema changes, sqlite supports "ALTER TABLE" syntax for certain operations (renaming the table or adding a column). This is an easy way to update existing tables in-place. See the documentation here: http://www.sqlite.org/lang_altertable.html. For deleting col...
Entity Framework - Invalid Column Name '*_ID"
...
What I have figured out is when you have an ICollection that references a table and there is no column that it can figure out, it creates one for you to try to make the connection between the tables. This specifically happens with ICollection and has driven me "batty" trying to figure it out.
...
How can I alter a primary key constraint using SQL syntax?
I have a table that is missing a column in its primary key constraint. Instead of editing it through SQL Server, I want to put this in a script to add it as part of our update scripts.
...
Add column to SQL Server
I need to add a column to my SQL Server table. Is it possible to do so without losing the data, I already have?
5 Answers...