40 lines
1.2 KiB
Crystal
40 lines
1.2 KiB
Crystal
module DB
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module BeginTransaction
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# Creates a transaction from the current context.
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# If is expected that either `Transaction#commit` or `Transaction#rollback`
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# are called explicitly to release the context.
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abstract def begin_transaction : Transaction
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# yields a transaction from the current context.
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# Query the database through `Transaction#connection` object.
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# If an exception is thrown within the block a rollback is performed.
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# The exception thrown is bubbled unless it is a `DB::Rollback`.
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# From the yielded object `Transaction#commit` or `Transaction#rollback`
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# can be called explicitly.
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# Returns the value of the block.
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def transaction(& : Transaction -> T) : T? forall T
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rollback = false
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# TODO: Cast to workaround crystal-lang/crystal#9483
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# begin_transaction returns a Tx where Tx < Transaction
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tx = begin_transaction.as(Transaction)
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begin
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res = yield tx
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rescue DB::Rollback
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rollback = true
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res
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rescue e
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rollback = true
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raise e
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ensure
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unless tx.closed?
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if rollback
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tx.rollback
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else
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tx.commit
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end
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end
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end
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end
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end
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end
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