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function _createMdxContent(props) {
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    p: "p",
    em: "em",
    code: "code",
    h2: "h2",
    a: "a",
    pre: "pre",
    span: "span",
    ul: "ul",
    li: "li"
  }, props.components), {Link} = _components;
  if (!Link) _missingMdxReference("Link", true);
  return _jsxs(_Fragment, {
    children: [_jsxs(_components.p, {
      children: [_jsx(_components.em, {
        children: "TL;DR As of 3.5, man­ag­ing data­base trans­ac­tions with Vert.x re­quires a lot of boil­er­plate code."
      }), "\n", _jsxs(_components.em, {
        children: ["Vert.x 3.6 will pro­vide helpers and ", _jsx(_components.code, {
          children: "Observable"
        }), " trans­form­ers to eas­ily make a re­ac­tive flow trans­ac­tional."]
      })]
    }), "\n", _jsxs(_components.h2, {
      id: "simple-queries-with-the-rxified-api",
      children: [_jsx(_components.a, {
        "aria-hidden": true,
        tabIndex: "-1",
        className: "heading-anchor",
        href: "#simple-queries-with-the-rxified-api"
      }), "Simple queries with the ", _jsx(_components.em, {
        children: "“Rxified”"
      }), " API"]
    }), "\n", _jsxs(_components.p, {
      children: ["The ", _jsx(Link, {
        href: "/docs/vertx-rx/java2/",
        passHref: true,
        children: _jsx(_components.a, {
          href: "",
          children: "Vert.x API for Rx­Java"
        })
      }), " is one of the most pop­u­lar mod­ules in the Vert.x stack."]
    }), "\n", _jsxs(_components.p, {
      children: ["So we make sure the ", _jsx(_components.em, {
        children: "“Rx­i­fied”"
      }), " API is easy to use for com­mon pro­gram­ming tasks, such as read­ing rows from a re­la­tional data­base and send­ing the re­sult to the client:"]
    }), "\n", _jsx(_components.pre, {
      children: _jsxs(_components.code, {
        className: "hljs language-java",
        children: ["dbClient.rxQuery(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"SELECT name, duration FROM tracks WHERE album = 'The Israelites'\""
        }), ")\n  .map(ResultSet::getResults)\n  .map(rows -> {\n    ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Transform DB rows into a client-friendly JSON object"
        }), "\n  })\n  .subscribe(json -> {\n    ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send JSON to the client"
        }), "\n  }, t -> {\n    ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send error to the client"
        }), "\n  });\n"]
      })
    }), "\n", _jsxs(_components.h2, {
      id: "managing-transactions-with-vertx-35",
      children: [_jsx(_components.a, {
        "aria-hidden": true,
        tabIndex: "-1",
        className: "heading-anchor",
        href: "#managing-transactions-with-vertx-35"
      }), "Managing transactions with Vert.x 3.5"]
    }), "\n", _jsx(_components.p, {
      children: "But very often, de­vel­op­ers have to im­ple­ment com­plex in­ter­ac­tions with the data­base, run­ning in­side a sin­gle trans­ac­tion.\nTo do so, the im­ple­men­ta­tion must fol­low this process:"
    }), "\n", _jsxs(_components.ul, {
      children: ["\n", _jsx(_components.li, {
        children: "get a con­nec­tion from the pool,"
      }), "\n", _jsx(_components.li, {
        children: "start a trans­ac­tion,"
      }), "\n", _jsx(_components.li, {
        children: "ex­e­cute queries,"
      }), "\n", _jsx(_components.li, {
        children: "if all queries suc­ceed, com­mit the trans­ac­tion,"
      }), "\n", _jsx(_components.li, {
        children: "oth­er­wise, roll­back the changes."
      }), "\n"]
    }), "\n", _jsx(_components.p, {
      children: "How does that trans­late to code?"
    }), "\n", _jsx(_components.pre, {
      children: _jsxs(_components.code, {
        className: "hljs language-java",
        children: [_jsx(_components.span, {
          className: "hljs-comment",
          children: "// Get a connection from the pool"
        }), "\ndbClient.rxGetConnection().flatMap(sqlConnection -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Setting auto-commit mode to false implicitely starts a transaction"
        }), "\n  ", _jsx(_components.span, {
          className: "hljs-keyword",
          children: "return"
        }), " sqlConnection.rxSetAutoCommit(", _jsx(_components.span, {
          className: "hljs-literal",
          children: "false"
        }), ")\n    .andThen(\n      ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Database queries"
        }), "\n      sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO albums (name) VALUES ('The Israelites')\""
        }), ")\n        .andThen(sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO tracks (album, name) VALUES ('The Israelites', 'Israelites')\""
        }), "))\n        .andThen(sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO tracks (album, name) VALUES ('The Israelites', 'Too Much Too Soon')\""
        }), "))\n        .andThen(sqlConnection.rxQuery(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"SELECT name FROM tracks WHERE album = 'The Israelites'\""
        }), ").map(ResultSet::getResults))\n    )\n    ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Commit if all queries succeed"
        }), "\n    .flatMap(rows -> sqlConnection.rxCommit().andThen(Single.just(rows)))\n    .onErrorResumeNext(throwable -> {\n      ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// On error, rollback the changes"
        }), "\n      ", _jsx(_components.span, {
          className: "hljs-keyword",
          children: "return"
        }), " sqlConnection.rxRollback().onErrorComplete()\n        .andThen(sqlConnection.rxSetAutoCommit(", _jsx(_components.span, {
          className: "hljs-literal",
          children: "true"
        }), ").onErrorComplete())\n        .andThen(Single.error(throwable));\n    }).flatMap(rows -> sqlConnection.rxSetAutoCommit(", _jsx(_components.span, {
          className: "hljs-literal",
          children: "true"
        }), ").andThen(Single.just(rows)))\n    .doFinally(sqlConnection::close);\n}).map(rows -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Transform DB rows into a client-friendly JSON object"
        }), "\n}).subscribe(json -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send JSON to the client"
        }), "\n}, t -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send error to the client"
        }), "\n});\n"]
      })
    }), "\n", _jsx(_components.p, {
      children: "That is a lot of boil­er­plate around the spe­cific data­base queries…\nIt would be bet­ter to re­lieve the de­vel­oper from main­tain­ing it."
    }), "\n", _jsxs(_components.h2, {
      id: "vertx-36-tools-for-transaction-management",
      children: [_jsx(_components.a, {
        "aria-hidden": true,
        tabIndex: "-1",
        className: "heading-anchor",
        href: "#vertx-36-tools-for-transaction-management"
      }), "Vert.x 3.6 tools for transaction management"]
    }), "\n", _jsxs(_components.p, {
      children: ["That is why Vert.x 3.6 will pro­vide ", _jsxs(_components.em, {
        children: [_jsx(_components.code, {
          children: "Observable"
        }), " trans­form­ers"]
      }), " that can be ap­plied to re­ac­tive flows with ", _jsx(_components.a, {
        href: "http://reactivex.io/RxJava/javadoc/io/reactivex/Flowable.html#compose-io.reactivex.FlowableTransformer-",
        children: _jsx(_components.code, {
          children: "compose"
        })
      }), " to make them trans­ac­tional:"]
    }), "\n", _jsxs(_components.ul, {
      children: ["\n", _jsx(_components.li, {
        children: _jsx(_components.code, {
          children: "SQLClientHelper#txFlowableTransformer"
        })
      }), "\n", _jsx(_components.li, {
        children: _jsx(_components.code, {
          children: "SQLClientHelper#txObservableTransformer"
        })
      }), "\n", _jsx(_components.li, {
        children: _jsx(_components.code, {
          children: "SQLClientHelper#txSingleTransformer"
        })
      }), "\n", _jsx(_components.li, {
        children: _jsx(_components.code, {
          children: "SQLClientHelper#txMaybeTransformer"
        })
      }), "\n", _jsx(_components.li, {
        children: _jsx(_components.code, {
          children: "SQLClientHelper#txCompletableTransformer"
        })
      }), "\n"]
    }), "\n", _jsxs(_components.p, {
      children: ["These ", _jsx(_components.em, {
        children: "trans­form­ers"
      }), " wrap the cor­re­spond­ing source of events with SQL trans­ac­tion man­age­ment."]
    }), "\n", _jsx(_components.pre, {
      children: _jsxs(_components.code, {
        className: "hljs language-java",
        children: ["dbClient.rxGetConnection().flatMap(sqlConnection -> {\n  ", _jsx(_components.span, {
          className: "hljs-keyword",
          children: "return"
        }), " sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO albums (name) VALUES ('The Israelites')\""
        }), ")\n    .andThen(sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO tracks (album, name) VALUES ('The Israelites', 'Israelites')\""
        }), "))\n    .andThen(sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO tracks (album, name) VALUES ('The Israelites', 'Too Much Too Soon')\""
        }), "))\n    .andThen(sqlConnection.rxQuery(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"SELECT name FROM tracks WHERE album = 'The Israelites'\""
        }), ").map(ResultSet::getResults))\n    .compose(SQLClientHelper.txSingleTransformer(sqlConnection))\n    .doFinally(sqlConnection::close);\n}).map(rows -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Transform DB rows into a client-friendly JSON object"
        }), "\n}).subscribe(json -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send JSON to the client"
        }), "\n}, t -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send error to the client"
        }), "\n});\n"]
      })
    }), "\n", _jsxs(_components.p, {
      children: ["Source ", _jsx(_components.em, {
        children: "trans­form­ers"
      }), " pro­vide max­i­mum flex­i­bil­ity: you are still able to ex­e­cute op­er­a­tions with the con­nec­tion after the trans­ac­tion com­pletes."]
    }), "\n", _jsxs(_components.p, {
      children: ["How­ever, you usu­ally do not need the con­nec­tion after the changes are ", _jsx(_components.em, {
        children: "com­mited"
      }), " or ", _jsx(_components.em, {
        children: "roll­backed"
      }), ".\nIn this case, you may sim­ply cre­ate you source ob­serv­able with one of the trans­ac­tional helper meth­ods in ", _jsx(_components.code, {
        children: "io.vertx.reactivex.ext.sql.SQLClientHelper"
      }), "."]
    }), "\n", _jsx(_components.p, {
      children: "Let’s rewrite the pre­vi­ous ex­am­ple:"
    }), "\n", _jsx(_components.pre, {
      children: _jsxs(_components.code, {
        className: "hljs language-java",
        children: ["SQLClientHelper.inTransactionSingle(client, sqlConnection -> {\n  ", _jsx(_components.span, {
          className: "hljs-keyword",
          children: "return"
        }), " sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO albums (name) VALUES ('The Israelites')\""
        }), ")\n    .andThen(sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO tracks (album, name) VALUES ('The Israelites', 'Israelites')\""
        }), "))\n    .andThen(sqlConnection.rxExecute(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"INSERT INTO tracks (album, name) VALUES ('The Israelites', 'Too Much Too Soon')\""
        }), "))\n    .andThen(sqlConnection.rxQuery(", _jsx(_components.span, {
          className: "hljs-string",
          children: "\"SELECT name FROM tracks WHERE album = 'The Israelites'\""
        }), ").map(ResultSet::getResults))\n}).map(rows -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Transform DB rows into a client-friendly JSON object"
        }), "\n}).subscribe(json -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send JSON to the client"
        }), "\n}, t -> {\n  ", _jsx(_components.span, {
          className: "hljs-comment",
          children: "// Send error to the client"
        }), "\n});\n"]
      })
    }), "\n", _jsxs(_components.h2, {
      id: "give-it-a-try",
      children: [_jsx(_components.a, {
        "aria-hidden": true,
        tabIndex: "-1",
        className: "heading-anchor",
        href: "#give-it-a-try"
      }), "Give it a try"]
    }), "\n", _jsxs(_components.p, {
      children: ["Vert.x 3.6 is ex­pected around fall, but the code is al­ready in mas­ter and ", _jsx(_components.em, {
        children: "snap­shots"
      }), " are reg­u­larly pub­lished to Sonatype’s OSS repos."]
    }), "\n", _jsxs(_components.p, {
      children: ["So give it a try and feel free to pro­vide your fee­back on our user or dev ", _jsx(Link, {
        href: "/community",
        passHref: true,
        children: _jsx(_components.a, {
          href: "",
          children: "chan­nels"
        })
      }), "."]
    })]
  });
}
function MDXContent(props = {}) {
  const {wrapper: MDXLayout} = props.components || ({});
  return MDXLayout ? _jsx(MDXLayout, Object.assign({}, props, {
    children: _jsx(_createMdxContent, props)
  })) : _createMdxContent(props);
}
return {
  default: MDXContent
};
function _missingMdxReference(id, component) {
  throw new Error("Expected " + (component ? "component" : "object") + " `" + id + "` to be defined: you likely forgot to import, pass, or provide it.");
}


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