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Rails: How to list database tables/objects using the Rails console?
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You are probably seeking:
ActiveRecord::Base.connection.tables
and
ActiveRecord::Base.connection.columns('projects').map(&:name)
You should probably wrap them in shorter syntax inside your .irbrc.
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Distinct in Linq based on only one field of the table
...am trying to use .distinct in Linq to get result based on one field of the table (so do not require a whole duplicated records from table).
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How do I cast a string to integer and have 0 in case of error in the cast with PostgreSQL?
In PostgreSQL I have a table with a varchar column. The data is supposed to be integers and I need it in integer type in a query. Some values are empty strings.
The following:
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What is the reason not to use select *?
...nt, the SQL execution engine will error if that column is removed from the table and the query is executed.
You can more easily scan code where that column is being used.
You should always write queries to bring back the least amount of information.
As others mention if you use ordinal column access...
How do I drop a foreign key constraint only if it exists in sql server?
I can drop a table if it exists using the following code but do not know how to do the same with a constraint:
10 Answers
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Entity Framework Join 3 Tables
I'm trying to join three tables but I can't understand the method...
2 Answers
2
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Swapping column values in MySQL
I have a MySQL table with coordinates, the column names are X and Y. Now I want to swap the column values in this table, so that X becomes Y and Y becomes X. The most apparent solution would be renaming the columns, but I don't want to make structure changes since I don't necessarily have permission...
Remove columns from dataframe where ALL values are NA
... function to reduce the size. The answer bellow using Filter or using data.table will help your memory usage.
– mtelesha
Dec 9 '15 at 15:21
3
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How to turn on/off ReactJS 'development mode'?
...ing the minified react will leave all those potential optimizations on the table as well.
Ultimately the magic comes down to React embedding references to process.env.NODE_ENV throughout the codebase; these act like a feature toggle.
if (process.env.NODE_ENV !== "production")
// do propType checks...
When to use MyISAM and InnoDB? [duplicate]
...s better for beginners. No worries about the foreign relationships between tables.
Faster than InnoDB on the whole as a result of the simpler structure thus much less costs of server resources. -- Mostly no longer true.
Full-text indexing. -- InnoDB has it now
Especially good for read-intensive (se...