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How To Change DataType of a DataColumn in a DataTable?
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You cannot change the DataType after the Datatable is filled with data. However, you can clone the Data table, change the column type and load data from previous data table to the cloned table as shown below.
DataTable dtCloned = dt.Clone();
dtCloned.Columns[0].DataTyp...
Add new column with foreign key constraint in one command
...to add the column and the foreign key constraint using two separate ALTER TABLE commands:
12 Answers
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how to get last insert id after insert query in codeigniter active record
...rt query (active record style) used to insert the form fields into a MySQL table. I want to get the last auto-incremented id for the insert operation as the return value of my query but I have some problems with it.
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How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?
My table is:
18 Answers
18
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CSS Cell Margin
In my HTML document, I have a table with two columns and multiple rows. How can I increase the space in between the first and second column with css? I've tried applying "margin-right: 10px;" to each of the cells on the left hand side, but to no effect.
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How to select the last record of a table in SQL?
This is a sample code to select all records from a table. Can someone show me how to select the last record of that table?
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MySQL how to join tables on two fields
I have two tables with date and id fields. I want to join on both fields. I tried
3 Answers
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Eager load polymorphic
...d is unable to build the join without additional information.
There is no table called reviewable
To solve this issue, you need to explicitly define the relationship between Review and Shop.
class Review < ActiveRecord::Base
belongs_to :user
belongs_to :reviewable, polymorphic: true
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How to drop multiple columns in postgresql
I want to drop 200 columns in my table in PostgreSQL. I tried:
2 Answers
2
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What makes a SQL statement sargable?
...sts. It will literally have to evaluate this function for every row of the table. Much better to use:
WHERE myDate >= '01-01-2008' AND myDate < '01-01-2009'
Some other examples:
Bad: Select ... WHERE isNull(FullName,'Ed Jones') = 'Ed Jones'
Fixed: Select ... WHERE ((FullName = 'Ed Jones') ...