大约有 37,000 项符合查询结果（耗时：0.0443秒） [XML]
Query for documents where array size is greater than 1
... @Tobia my first use was $exists only but it actually use whole table scan so very slow. db.test.find({"name":"abc","d.5":{$exists:true},"d.6":{$exists:true}}) "nReturned" : 46525, "executionTimeMillis" : 167289, "totalKeysExamined" : 10990840, "totalDocsExamined" : 10990840, ...
How do I see active SQL Server connections?
...ys.sysprocesses WHERE dbid > 0
--Available connections
DECLARE @SPWHO1 TABLE (DBName VARCHAR(1000) NULL, NoOfAvailableConnections VARCHAR(1000) NULL, LoginName VARCHAR(1000) NULL)
INSERT INTO @SPWHO1
SELECT db_name(dbid), count(dbid), loginame FROM sys.sysprocesses WHERE dbid > 0 GROUP B...
hexadecimal string to byte array in python
...hex(hex_string)
bytearray(b'\xde\xad\xbe\xef')
Note that bytes is an immutable version of bytearray.
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How to convert SQL Query result to PANDAS Data Structure?
...ctor not properly called!, it appears that the tuple of tuples is not acceptable for DataFrame constructor. There is also no .keys() on cursor either in dictionary or tuple mode.
– Mobigital
Jan 20 '19 at 20:45
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Unique constraint that allows empty values in MySQL
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@MianAnjum bolded: CREATE TABLE table (key int(11) NOT NULL AUTO_INCREMENT, field tinyint(1) DEFAULT NULL)
– Paul Nowak
Sep 19 '17 at 19:45
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Storing sex (gender) in database
...the 'closest' data type would be tinyint with a CHECK constraint or lookup table as appropriate.
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SQL how to make null values come last when sorting ascending
I have a SQL table with a datetime field. The field in question can be null. I have a query and I want the results sorted ascendingly by the datetime field, however I want rows where the datetime field is null at the end of the list, not at the beginning.
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How do you convert a byte array to a hexadecimal string, and vice versa?
...)
Text: 718,380.63 (1.0X faster)
Sentence: 39.71 (1.0X faster)
Lookup tables have taken the lead over byte manipulation. Basically, there is some form of precomputing what any given nibble or byte will be in hex. Then, as you rip through the data, you simply look up the next portion to see what...
Entity Framework 4 vs NHibernate [closed]
...hat EF4 has more flexible inheritance mapping. For instance, you can use 2 tables (TPT) as base class + level 1 class and add discriminator to level 1 table, allowing spliting to level 2 classes. In NH, discriminator can only be defined on base class.
– Danny Varod
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Is “ ” a replacement of “ ”?
... the same except for the fact that the latter does not need another lookup table to find its actual value. The lookup table is called a DTD, by the way.
You can read more about character entity references in the offical W3C documents.
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