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Product typeBook
Published inJan 2016
Reading LevelIntermediate
Publisher
ISBN-139781785281372
Edition1st Edition
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Pascal Bugnion
Pascal Bugnion
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Pascal Bugnion

Pascal Bugnion is a data engineer at the ASI, a consultancy offering bespoke data science services. Previously, he was the head of data engineering at SCL Elections. He holds a PhD in computational physics from Cambridge University. Besides Scala, Pascal is a keen Python developer. He has contributed to NumPy, matplotlib and IPython. He also maintains scikit-monaco, an open source library for Monte Carlo integration. He currently lives in London, UK.
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Enriching JDBC statements with the "pimp my library" pattern


In the previous section, we saw how to create self-closing connections with the loan pattern. This allows us to open connections to the database without having to remember to close them. However, we still have to remember to close any ResultSet and PreparedStatement that we open:

// WARNING: Poor Scala code
SqlUtils.usingConnection("test") { connection =>
  val statement = connection.prepareStatement(
    "SELECT * FROM physicists")
  val results = statement.executeQuery
  // do something useful with the results
  results.close
  statement.close
}

Having to open and close the statement is somewhat ugly and error prone. This is another natural use case for the loan pattern. Ideally, we would like to write the following:

usingConnection("test") { connection =>
  connection.withQuery("SELECT * FROM physicists") {
    resultSet => // process results
  }
}

How can we define a .withQuery method on the Connection class? We do not...

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Scala for Data Science
Published in: Jan 2016Publisher: ISBN-13: 9781785281372

Author (1)

author image
Pascal Bugnion

Pascal Bugnion is a data engineer at the ASI, a consultancy offering bespoke data science services. Previously, he was the head of data engineering at SCL Elections. He holds a PhD in computational physics from Cambridge University. Besides Scala, Pascal is a keen Python developer. He has contributed to NumPy, matplotlib and IPython. He also maintains scikit-monaco, an open source library for Monte Carlo integration. He currently lives in London, UK.
Read more about Pascal Bugnion