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Can table columns with a Foreign Key be NULL?
I have a table which has several ID columns to other tables.
7 Answers
7
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The model backing the context has changed since the database was created
...eded to use the model with a hash of the schema stored in an
EdmMetadata table that is created with a database (when Code First is
the one creating the database). Existing databases won’t have the
EdmMetadata table and so won’t have the hash…and the implementation
today will throw if t...
How to find third or nth maximum salary from salary table?
How to find third or nth maximum salary from salary table(EmpID,EmpName,EmpSalary) in Optimized way?
54 Answers
...
Position of least significant bit that is set
...how to squeeze some cycles out of it?" makes such an answer perfectly acceptable!
– Mehrdad Afshari
Apr 16 '09 at 17:08
5
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Alter Table Add Column Syntax
I'm trying to programmatically add an identity column to a table Employees. Not sure what I'm doing wrong with my syntax.
4...
Real life example, when to use OUTER / CROSS APPLY in SQL
...ORDER BY pr.name) pa
ORDER BY pr.name,
pa.name
2) Calling a Table Valued Function for each row in the outer query
SELECT *
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle)
3) Reusing a column alias
SELECT number,
doubled_number,
...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...
SELECT
table1.*
, table2.*
INNER JOIN table2 ON table2.SomeFkId = table1.SomeId
That gets you a result set where child rows in table2 cause duplication by returning the table1 results for each child row in table2. O/R mappers sho...
Pass Array Parameter in SqlCommand
...arameters[i], items[i]);
}
cmd.CommandText = string.Format("SELECT * from TableA WHERE Age IN ({0})", string.Join(", ", parameters));
cmd.Connection = new SqlConnection(connStr);
UPDATE: Here is an extended and reusable solution that uses Adam's answer along with his suggested edit. I improved it...
What's the $unwind operator in MongoDB?
..., consider this array tags : [ "fun" , "good" , "fun" ] as another related table (can't be a lookup/reference table because values has some duplication) named "tags". Remember SELECT generally produces things vertical, so unwind the "tags" is to split() vertically into table "tags".
The end result ...
MYSQL import data from csv using LOAD DATA INFILE
...
You can use LOAD DATA INFILE command to import csv file into table.
Check this link MySQL - LOAD DATA INFILE.
LOAD DATA LOCAL INFILE 'abc.csv' INTO TABLE abc
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\r\n'
IGNORE 1 LINES
(col1, col2, col3, col4, col5...);
For...