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Transaction, what is a transaction?

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We hear this a lot in databases, a transaction, it's nothing but a bunch of queries.

3
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OK, it's a collection of queries.

4
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So it's a one or more queries game.

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And that property of these queries or they are you one unit of work?

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An example would be if you want to deposit an account.

7
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Right.

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And some cash into an account that is actually a select statement followed by a statement followed by

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another update, something like we now we're going to show in the second round.

10
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But each one of those is a query.

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The three of them can form a transaction and you define what a transaction begin and where transaction

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end.

13
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And we also there is another semantic attached to a transaction like a commit.

14
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Hey, I am happy with my changes.

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Go persist them, commit that sort of commitment, roll back.

16
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You know what I think something went wrong.

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Roll back, abort, abort, abort.

18
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So that's another two piece of concept then attach by a transaction.

19
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We know that.

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Let's just jump into example.

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A transaction.

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I have an account here with a beautiful table just to feel because that's all where you need obviously

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for in a bank or I have to.

24
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Still feels like you don't need a name.

25
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You don't need anything else.

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No data, no.

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Just do field.

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So there's I got the idea there is a balance.

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This guy has a thousand dollars, guys added to five, five hundred.

30
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And the transaction is send hundred dollars from account one to account to us.

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So what do we need to do first.

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Does account one even have a hundred dollar.

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I don't know.

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So I need to check to us, we're going to begin the transaction, get a select let's check the balance.

35
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Do you have one hundred dollars that.

36
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Yes.

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Your balance is a balance.

38
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Go to the 100 yard sir.

39
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It is greater than a hundred.

40
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All right.

41
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Let's debit that hundred minus hundred.

42
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OK, so now it's nine hundred.

43
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OK, but that's not committed is just the math, right?

44
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It's just touched.

45
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It's a dirty change game.

46
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And then I'm going to add another hundred to the second account.

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I'm going to commit my changes.

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Turning green.

49
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I mean, this is like it's persisted.

50
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All good.

51
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We're happy and that's it.

52
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OK, so that's essentially what a transaction is.

53
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It's a unit of work, but it consists of multiple queries, one or more as a transaction.