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EF Code First “Invalid column name 'Discriminator'” but no inheritance
I have a table in my database called SEntries (see below the CREATE TABLE statement). It has a primary key, a couple of foreign keys and nothing special about it. I have many tables in my database similar to that one, but for some reason, this table ended up with a "Discriminator" column on the EF P...
Multiple Updates in MySQL
... use INSERT ... ON DUPLICATE KEY UPDATE.
Using your example:
INSERT INTO table (id,Col1,Col2) VALUES (1,1,1),(2,2,3),(3,9,3),(4,10,12)
ON DUPLICATE KEY UPDATE Col1=VALUES(Col1),Col2=VALUES(Col2);
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Rename a table in MySQL
Renaming a table is not working in MySQL
16 Answers
16
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The ALTER TABLE statement conflicted with the FOREIGN KEY constraint
I have a problem when trying to add a foreign key to my tblDomare table; what am I doing wrong here?
18 Answers
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What's the difference between TRUNCATE and DELETE in SQL
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General Overview
If you want to quickly delete all of the rows from a table, and you're really sure that you want to do it, and you do not have foreign keys against the tables, then a TRUNCATE is probably going to be faster than a DELETE.
Various system-specific issues have to be considered, a...
Vertically centering a div inside another div [duplicate]
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tl;dr
Vertical align middle works, but you will have to use table-cell on your parent element and inline-block on the child.
This solution is not going to work in IE6 & 7. Yours is the safer way to go for those. But since you tagged your question with CSS3 and HTML5 I was thinkin...
Why is SELECT * considered harmful?
...work. This is especially true when someone adds new columns to underlying tables that didn't exist and weren't needed when the original consumers coded their data access.
Indexing issues. Consider a scenario where you want to tune a query to a high level of performance. If you were to use *, and ...
SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
...ver MySQL. In my case, the source and destination columns are in the same table, but record selection is based on the other table. The "SELECT" version of the query works, but the UPDTATE statement throws a syntax error at "FROM"
– 2NinerRomeo
Mar 4 '15 at 19...
SQL DROP TABLE foreign key constraint
If I want to delete all the tables in my database like this, will it take care of the foreign key constraint? If not, how do I take care of that first?
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Why should hash functions use a prime number modulus?
A long time ago, I bought a data structures book off the bargain table for $1.25. In it, the explanation for a hashing function said that it should ultimately mod by a prime number because of "the nature of math".
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