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What is hashCode used for? Is it unique?
...n index for an object
in a collection.
The GetHashCode method is suitable for use in hashing algorithms and
data structures such as a hash table.
The default implementation of the GetHashCode method does not
guarantee unique return values for different objects. Furthermore, the
.NE...
Is there a MySQL command to convert a string to lowercase?
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UPDATE table SET colname=LOWER(colname);
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Received an invalid column length from the bcp client for colid 6
...the data in the excel for its format to be in compliance with the database table schema.
To avoid this, try exceeding the data-length of the string datatype in the database table.
Hope this helps.
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How to keep index when using pandas merge
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Think I've come up with a different solution. I was joining the left table on index value and the right table on a column value based off index of left table. What I did was a normal merge:
First10ReviewsJoined = pd.merge(First10Reviews, df, left_index=True, right_on='Line Number')
Then I r...
sql primary key and index
...ou may reach the desired optimization for a query.
For example you have a table with many columns but you are only querying ID, Name and Address columns. Taking ID as the primary key, we can create the following index that is built on ID but includes Name and Address columns.
CREATE NONCLUSTERED I...
What is “with (nolock)” in SQL Server?
...'t ever rollback transactions, that doesn't matter. And with a insert-only table, the chances of a rollback are slim to none. And if they do occur, you will still fix it all in the end of day variance report.
– Jonathan Allen
Mar 27 '09 at 18:47
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Postgresql GROUP_CONCAT equivalent?
I have a table and I'd like to pull one row per id with field values concatenated.
7 Answers
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Insert/Update Many to Many Entity Framework . How do I do it?
...a Student object that has a collection of Classes. Since your StudentClass table only contains the Ids and no extra information, EF does not generate an entity for the joining table. That is the correct behaviour and that's what you expect.
Now, when doing inserts or updates, try to think in terms ...
phpcms与ucenter整合常见问题与解答 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...onnect(UC_DBHOST, UC_DBUSER, UC_DBPW, '', UC_DBCHARSET, UC_DBCONNECT, UC_DBTABLEPRE);
替换为：
代码示例:
$this->db->connect(UC_DBHOST, UC_DBUSER, UC_DBPW, UC_DBNAME, UC_DBCHARSET, UC_DBCONNECT, UC_DBTABLEPRE);
2、为什么不使用官方自带的 UCenter 客户端？
答：官方自...
data.frame rows to a list
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@AaronMcDaid Or data.table::rbindlist(). If your original data frame was large, the speed gains will be significant.
– Empiromancer
Jul 12 '16 at 22:04
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