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SQLite in Android How to update a specific row
...2","Male");
Then use the update method, it should work now:
myDB.update(TableName, cv, "_id="+id, null);
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ALTER TABLE to add a composite primary key
I have a table called provider . I have three columns called person , place , thing . There can be duplicate persons, duplicate places, and duplicate things, but there can never be a dupicate person-place-thing combination.
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Why does Java switch on contiguous ints appear to run faster with added cases?
...ed to sparse), the generated bytecode for your various tests uses a switch table (bytecode instruction tableswitch).
However, once the JIT starts its job and compiles the bytecode into assembly, the tableswitch instruction does not always result in an array of pointers: sometimes the switch table i...
How to delete migration files in Rails 3
... or staging, it's safer to just write another migration that destroys your table or columns.
Another great reference for migrations is: http://guides.rubyonrails.org/migrations.html
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How do you convert a DataTable into a generic list?
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If you're using .NET 3.5, you can use DataTableExtensions.AsEnumerable (an extension method) and then if you really need a List<DataRow> instead of just IEnumerable<DataRow> you can call Enumerable.ToList:
IEnumerable<DataRow> sequence = dt.AsEnume...
How to pass table value parameters to stored procedure from .net code
I have a SQL Server 2005 database. In a few procedures I have table parameters that I pass to a stored proc as an nvarchar (separated by commas) and internally divide into single values. I add it to the SQL command parameters list like this:
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MySQL case insensitive select
...in did mention collate was better) We had historical data moved into mysql table which broke legacy logic because of certain column values having insensitive case. We needed to know the difference between "GE1234" and "ge1234", they needed to be unique and stay logged that way. We set our column in ...
Django migration strategy for renaming a model and relationship fields
...different name, and the migration it creates will lose any data in the old table." Django 2.1 Docs For me, it was sufficient to create an empty migration, add the model renames to it, then run makemigrations as usual.
– hlongmore
Jan 15 '19 at 9:05
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Improve INSERT-per-second performance of SQLite
...f possible, which will replace the implied unique row number column in the table.
If you are using multiple threads, you can try using the shared page cache, which will allow loaded pages to be shared between threads, which can avoid expensive I/O calls.
Don't use !feof(file)!
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Python Pandas merge only certain columns
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This is to merge selected columns from two tables.
If table_1 contains t1_a,t1_b,t1_c..,id,..t1_z columns,
and table_2 contains t2_a, t2_b, t2_c..., id,..t2_z columns,
and only t1_a, id, t2_a are required in the final table, then
mergedCSV = table_1[['t1_a','id']].m...