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find vs find_by vs where
I am new to rails. What I see that there are a lot of ways to find a record:
12 Answers
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Can a foreign key be NULL and/or duplicate?
Please clarify two things for me:
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How to Create a circular progressbar in Android which rotates on it?
I am trying to create a rounded progressbar. This is what I want to achieve
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Update multiple rows in same query using PostgreSQL
I'm looking to update multiple rows in PostgreSQL in one statement. Is there a way to do something like the following?
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Rails auto-assigning id that already exists
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Rails is probably using the built-in PostgreSQL sequence. The idea of a sequence is that it is only used once.
The simplest solution is to set the sequence for your company.id column to the highest value in the table with a query like this:
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How to add a button dynamically in Android?
How to add a button dynamically in Android?
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INSERT IF NOT EXISTS ELSE UPDATE?
I've found a few "would be" solutions for the classic "How do I insert a new record or update one if it already exists" but I cannot get any of them to work in SQLite.
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Create unique constraint with null columns
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Create two partial indexes:
CREATE UNIQUE INDEX favo_3col_uni_idx ON favorites (user_id, menu_id, recipe_id)
WHERE menu_id IS NOT NULL;
CREATE UNIQUE INDEX favo_2col_uni_idx ON favorites (user_id, recipe_id)
WHERE menu_id IS NULL;
This way,...
OnNotify函数 ON_NOTIFY消息总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...的定义
typedef struct tagNMHDR
{
HWND hwndFrom;
UINT_PTR idFrom;
UINT code; // NM_ code
} NMHDR;
通过分析代码发现：
hwndFrom：必须有，声明消息来自哪个窗口。
idFrom：可有可无，声明窗口ID
code：具体的子消息...
Ordering by the order of values in a SQL IN() clause
I am wondering if there is away (possibly a better way) to order by the order of the values in an IN() clause.
13 Answers
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