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Module Identifier

erbix/query

• Overview
• Query Objects
• JavaScript Database Connectivity Package
• Obtaining Database Connections
• Executing Statements With execute Method
• Retrieving Results With queryForList Method

Overview

The erbix/query module is a DRAFT API. It is not standardized and currently it is Erbix-specific.

The erbix/query module is used in order to interact with the account's database. Each Erbix account is linked to a dedicated database instance powered by an SQL engine.

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Query Objects

Erbix uses query objects to identify connections to the database.

Each time you want to send an SQL command to the database server or to get back results, you'll need a query object. It can be obtained using the newQuery() function:

var myQuery = require("erbix/query").newQuery();

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JavaScript Database Connectivity (JSDBC)

The jsdbc is an accessor for the JavaScript Database Connectivity class package. It should be used to access static fields.

require("erbix/query").jsdbc.Statement.RETURN_GENERATED_KEYS;

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Obtaining Database Connections

The getConnection function returns the Connection object to the account's PostgreSQL database. See JavaScript Database Connectivity documentation for more details.

var conn = require("erbix/query").getConnection();

-OR-

var query = require("erbix/query").newQuery();
var conn = query.getConnection();

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Executing Statements With execute Method

execute(sql, params) executes a prepared statement.

• parameter sql: a string that may contain any number of '?' parameter placeholders.
• parameter params (optional): an array of objects in equal number as the '?' placeholders in sql parameter.
• return: null in case of success or a string with the error message in case of failure

Here's an example for executing an insert:

  var query = require("erbix/query");
  var myQuery = query.newQuery();
  myQuery.execute(
      "INSERT INTO table_name(name, email, message) VALUES(?, ?, ?);",
      ["Simon", "simon@gmail.com", "Hello!"]
  );

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Retrieving Results With queryForList Method

queryForList(sql, params) executes a prepared statement that returns a single result set.

• parameter sql: a string that may contain any number of '?' parameter placeholders.
• parameter params (optional): an array of objects in equal number as the '?' placeholders in sql parameter.
• return: 1) if successful: an array of hashes (one hash per row result) having as keys the column names and as values the data contained in each row result column. 2) on error: a string with the error message.

  var query = require("erbix/query");
  var myQuery = query.newQuery();

  var result = myQuery.queryForList(
      "SELECT id, name FROM persons WHERE age > ? AND surname = ?",
      [20, 'Mark']);