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Engine Class

Engine.Rd

The Engine class is a core component of the oRm framework, responsible for managing database connections and providing methods for interacting with the database. It supports both direct connections and connection pooling, offering flexibility in how database resources are managed.

Key features:

  • Manages database connections (single or pooled)

  • Provides methods for executing SQL queries and commands

  • Allows creation of TableModel objects for ORM operations

  • Supports persistent connections for improved performance

Methods

Public methods

Method new()

Usage

Engine$new(..., conn_args = list(), use_pool = FALSE, persist = FALSE)

Arguments

...

args to be passed to DBI::dbConnect

conn_args

args to be passed to DBI::dbConnect

use_pool

whether or not to make use of the pool package for connections to this engine

persist

whether to keep the connection open after operations (default: FALSE)

Get a connection to the database

Method get_connection()

Usage

Engine$get_connection()

Returns

A DBIConnection object or a pool object Close the database connection or pool list tables in the database connection Execute a SQL query and return the result as a data.frame

Method close()

Usage

Engine$close()

Method list_tables()

Usage

Engine$list_tables()

Method get_query()

Usage

Engine$get_query(sql)

Arguments

sql

SQL query

Returns

A data.frame Execute a SQL query and return the number of rows affected Create a new TableModel object for the specified table

Method execute()

Usage

Engine$execute(sql)

Method model()

Usage

Engine$model(tablename, ..., .data = list())

Arguments

tablename

Name of the table

...

Additional arguments passed to the TableModel constructor

.data

a named list of the arguments for the TableModel constructor

Method clone()

The objects of this class are cloneable with this method.

Usage

Engine$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.