require 'active_record/connection_adapters/abstract_adapter'
require 'active_record/connection_adapters/statement_pool'
require 'arel/visitors/bind_visitor'
gem 'sqlite3', '~> 1.3.6'
require 'sqlite3'
module ActiveRecord
module ConnectionHandling
# sqlite3 adapter reuses sqlite_connection.
def sqlite3_connection(config) # :nodoc:
# Require database.
unless config[:database]
raise ArgumentError, "No database file specified. Missing argument: database"
end
# Allow database path relative to Rails.root, but only if
# the database path is not the special path that tells
# Sqlite to build a database only in memory.
if defined?(Rails.root) && ':memory:' != config[:database]
config[:database] = File.expand_path(config[:database], Rails.root)
end
unless 'sqlite3' == config[:adapter]
raise ArgumentError, 'adapter name should be "sqlite3"'
end
db = SQLite3::Database.new(
config[:database],
:results_as_hash => true
)
db.busy_timeout(config[:timeout]) if config[:timeout]
ConnectionAdapters::SQLite3Adapter.new(db, logger, config)
end
end
module ConnectionAdapters #:nodoc:
class SQLite3Column < Column #:nodoc:
class << self
def binary_to_string(value)
if value.encoding != Encoding::ASCII_8BIT
value = value.force_encoding(Encoding::ASCII_8BIT)
end
value
end
end
end
# The SQLite3 adapter works with SQLite 3.6.16 or newer,
# with the sqlite3-ruby drivers (available as gem from https://rubygems.org/gems/sqlite3).
#
# Options:
#
# * <tt>:database</tt> - Path to the database file.
class SQLite3Adapter < AbstractAdapter
class Version
include Comparable
def initialize(version_string)
@version = version_string.split('.').map { |v| v.to_i }
end
def <=>(version_string)
@version <=> version_string.split('.').map { |v| v.to_i }
end
end
class StatementPool < ConnectionAdapters::StatementPool
def initialize(connection, max)
super
@cache = Hash.new { |h,pid| h[pid] = {} }
end
def each(&block); cache.each(&block); end
def key?(key); cache.key?(key); end
def [](key); cache[key]; end
def length; cache.length; end
def []=(sql, key)
while @max <= cache.size
dealloc(cache.shift.last[:stmt])
end
cache[sql] = key
end
def clear
cache.values.each do |hash|
dealloc hash[:stmt]
end
cache.clear
end
private
def cache
@cache[$$]
end
def dealloc(stmt)
stmt.close unless stmt.closed?
end
end
class BindSubstitution < Arel::Visitors::SQLite # :nodoc:
include Arel::Visitors::BindVisitor
end
def initialize(connection, logger, config)
super(connection, logger)
@statements = StatementPool.new(@connection,
config.fetch(:statement_limit) { 1000 })
@config = config
if config.fetch(:prepared_statements) { true }
@visitor = Arel::Visitors::SQLite.new self
else
@visitor = BindSubstitution.new self
end
end
def adapter_name #:nodoc:
'SQLite'
end
# Returns true, since this connection adapter supports ddl transactions.
def supports_ddl_transactions?
true
end
# Returns true if SQLite version supports savepoints, false otherwise.
def supports_savepoints?
sqlite_version >= '3.6.8'
end
# Returns true, since this connection adapter supports prepared statement.
# caching.
def supports_statement_cache?
true
end
# Returns true, since this connection adapter supports migrations.
def supports_migrations? #:nodoc:
true
end
# Returns true, since this connection adapter supports primary key.
def supports_primary_key? #:nodoc:
true
end
def requires_reloading?
true
end
# Returns true, since this connection adapter supports add column.
def supports_add_column?
true
end
# Disconnects from the database if already connected.
def disconnect!
super
clear_cache!
@connection.close rescue nil
end
# Clears the prepared statements cache.
def clear_cache!
@statements.clear
end
# Returns true, since this connection adapter count distinct.
def supports_count_distinct? #:nodoc:
true
end
# Returns true, since this connection adapter supports autoincrement.
def supports_autoincrement? #:nodoc:
true
end
# Returns true, since this connection adapter supports
def supports_index_sort_order?
true
end
def native_database_types #:nodoc:
{
:primary_key => default_primary_key_type,
:string => { :name => "varchar", :limit => 255 },
:text => { :name => "text" },
:integer => { :name => "integer" },
:float => { :name => "float" },
:decimal => { :name => "decimal" },
:datetime => { :name => "datetime" },
:timestamp => { :name => "datetime" },
:time => { :name => "time" },
:date => { :name => "date" },
:binary => { :name => "blob" },
:boolean => { :name => "boolean" }
}
end
# Returns the current database encoding format as a string, eg: 'UTF-8'
def encoding
@connection.encoding.to_s
end
# Returns true, since this connection adapter supports explain.
def supports_explain?
true
end
# QUOTING ==================================================
def quote(value, column = nil)
if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
s = column.class.string_to_binary(value).unpack("H*")[0]
"x'#{s}'"
else
super
end
end
def quote_string(s) #:nodoc:
@connection.class.quote(s)
end
def quote_column_name(name) #:nodoc:
%Q("#{name.to_s.gsub('"', '""')}")
end
# Quote date/time values for use in SQL input. Includes microseconds
# if the value is a Time responding to usec.
def quoted_date(value) #:nodoc:
if value.respond_to?(:usec)
"#{super}.#{sprintf("%06d", value.usec)}"
else
super
end
end
def type_cast(value, column) # :nodoc:
return value.to_f if BigDecimal === value
return super unless String === value
return super unless column && value
value = super
if column.type == :string && value.encoding == Encoding::ASCII_8BIT
logger.error "Binary data inserted for `string` type on column `#{column.name}`" if logger
value.encode! 'utf-8'
end
value
end
# DATABASE STATEMENTS ======================================
def explain(arel, binds = [])
sql = "EXPLAIN QUERY PLAN #{to_sql(arel, binds)}"
ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
end
class ExplainPrettyPrinter
# Pretty prints the result of a EXPLAIN QUERY PLAN in a way that resembles
# the output of the SQLite shell:
#
# 0|0|0|SEARCH TABLE users USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
# 0|1|1|SCAN TABLE posts (~100000 rows)
#
def pp(result) # :nodoc:
result.rows.map do |row|
row.join('|')
end.join("\n") + "\n"
end
end
def exec_query(sql, name = nil, binds = [])
log(sql, name, binds) do
# Don't cache statements without bind values
if binds.empty?
stmt = @connection.prepare(sql)
cols = stmt.columns
records = stmt.to_a
stmt.close
stmt = records
else
cache = @statements[sql] ||= {
:stmt => @connection.prepare(sql)
}
stmt = cache[:stmt]
cols = cache[:cols] ||= stmt.columns
stmt.reset!
stmt.bind_params binds.map { |col, val|
type_cast(val, col)
}
end
ActiveRecord::Result.new(cols, stmt.to_a)
end
end
def exec_delete(sql, name = 'SQL', binds = [])
exec_query(sql, name, binds)
@connection.changes
end
alias :exec_update :exec_delete
def last_inserted_id(result)
@connection.last_insert_row_id
end
def execute(sql, name = nil) #:nodoc:
log(sql, name) { @connection.execute(sql) }
end
def update_sql(sql, name = nil) #:nodoc:
super
@connection.changes
end
def delete_sql(sql, name = nil) #:nodoc:
sql += " WHERE 1=1" unless sql =~ /WHERE/i
super sql, name
end
def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #:nodoc:
super
id_value || @connection.last_insert_row_id
end
alias :create :insert_sql
def select_rows(sql, name = nil)
exec_query(sql, name).rows
end
def create_savepoint
execute("SAVEPOINT #{current_savepoint_name}")
end
def rollback_to_savepoint
execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end
def release_savepoint
execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end
def begin_db_transaction #:nodoc:
log('begin transaction',nil) { @connection.transaction }
end
def commit_db_transaction #:nodoc:
log('commit transaction',nil) { @connection.commit }
end
def rollback_db_transaction #:nodoc:
log('rollback transaction',nil) { @connection.rollback }
end
# SCHEMA STATEMENTS ========================================
def tables(name = 'SCHEMA', table_name = nil) #:nodoc:
sql = <<-SQL
SELECT name
FROM sqlite_master
WHERE type = 'table' AND NOT name = 'sqlite_sequence'
SQL
sql << " AND name = #{quote_table_name(table_name)}" if table_name
exec_query(sql, name).map do |row|
row['name']
end
end
def table_exists?(name)
name && tables('SCHEMA', name).any?
end
# Returns an array of +SQLite3Column+ objects for the table specified by +table_name+.
def columns(table_name) #:nodoc:
table_structure(table_name).map do |field|
case field["dflt_value"]
when /^null$/i
field["dflt_value"] = nil
when /^'(.*)'$/
field["dflt_value"] = $1.gsub("''", "'")
when /^"(.*)"$/
field["dflt_value"] = $1.gsub('""', '"')
end
SQLite3Column.new(field['name'], field['dflt_value'], field['type'], field['notnull'].to_i == 0)
end
end
# Returns an array of indexes for the given table.
def indexes(table_name, name = nil) #:nodoc:
exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", name).map do |row|
IndexDefinition.new(
table_name,
row['name'],
row['unique'] != 0,
exec_query("PRAGMA index_info('#{row['name']}')").map { |col|
col['name']
})
end
end
def primary_key(table_name) #:nodoc:
column = table_structure(table_name).find { |field|
field['pk'] == 1
}
column && column['name']
end
def remove_index!(table_name, index_name) #:nodoc:
exec_query "DROP INDEX #{quote_column_name(index_name)}"
end
# Renames a table.
#
# Example:
# rename_table('octopuses', 'octopi')
def rename_table(name, new_name)
exec_query "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}"
end
# See: http://www.sqlite.org/lang_altertable.html
# SQLite has an additional restriction on the ALTER TABLE statement
def valid_alter_table_options( type, options)
type.to_sym != :primary_key
end
def add_column(table_name, column_name, type, options = {}) #:nodoc:
if supports_add_column? && valid_alter_table_options( type, options )
super(table_name, column_name, type, options)
else
alter_table(table_name) do |definition|
definition.column(column_name, type, options)
end
end
end
def remove_column(table_name, *column_names) #:nodoc:
raise ArgumentError.new("You must specify at least one column name. Example: remove_column(:people, :first_name)") if column_names.empty?
column_names.each do |column_name|
alter_table(table_name) do |definition|
definition.columns.delete(definition[column_name])
end
end
end
alias :remove_columns :remove_column
def change_column_default(table_name, column_name, default) #:nodoc:
alter_table(table_name) do |definition|
definition[column_name].default = default
end
end
def change_column_null(table_name, column_name, null, default = nil)
unless null || default.nil?
exec_query("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
end
alter_table(table_name) do |definition|
definition[column_name].null = null
end
end
def change_column(table_name, column_name, type, options = {}) #:nodoc:
alter_table(table_name) do |definition|
include_default = options_include_default?(options)
definition[column_name].instance_eval do
self.type = type
self.limit = options[:limit] if options.include?(:limit)
self.default = options[:default] if include_default
self.null = options[:null] if options.include?(:null)
self.precision = options[:precision] if options.include?(:precision)
self.scale = options[:scale] if options.include?(:scale)
end
end
end
def rename_column(table_name, column_name, new_column_name) #:nodoc:
unless columns(table_name).detect{|c| c.name == column_name.to_s }
raise ActiveRecord::ActiveRecordError, "Missing column #{table_name}.#{column_name}"
end
alter_table(table_name, :rename => {column_name.to_s => new_column_name.to_s})
end
def empty_insert_statement_value
"VALUES(NULL)"
end
protected
def select(sql, name = nil, binds = []) #:nodoc:
exec_query(sql, name, binds)
end
def table_structure(table_name)
structure = exec_query("PRAGMA table_info(#{quote_table_name(table_name)})", 'SCHEMA').to_hash
raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
structure
end
def alter_table(table_name, options = {}) #:nodoc:
altered_table_name = "altered_#{table_name}"
caller = lambda {|definition| yield definition if block_given?}
transaction do
move_table(table_name, altered_table_name,
options.merge(:temporary => true))
move_table(altered_table_name, table_name, &caller)
end
end
def move_table(from, to, options = {}, &block) #:nodoc:
copy_table(from, to, options, &block)
drop_table(from)
end
def copy_table(from, to, options = {}) #:nodoc:
from_primary_key = primary_key(from)
options[:primary_key] = from_primary_key if from_primary_key != 'id'
unless options[:primary_key]
options[:id] = columns(from).detect{|c| c.name == 'id'}.present? && from_primary_key == 'id'
end
create_table(to, options) do |definition|
@definition = definition
columns(from).each do |column|
column_name = options[:rename] ?
(options[:rename][column.name] ||
options[:rename][column.name.to_sym] ||
column.name) : column.name
@definition.column(column_name, column.type,
:limit => column.limit, :default => column.default,
:precision => column.precision, :scale => column.scale,
:null => column.null)
end
@definition.primary_key(primary_key(from)) if primary_key(from)
yield @definition if block_given?
end
copy_table_indexes(from, to, options[:rename] || {})
copy_table_contents(from, to,
@definition.columns.map {|column| column.name},
options[:rename] || {})
end
def copy_table_indexes(from, to, rename = {}) #:nodoc:
indexes(from).each do |index|
name = index.name
if to == "altered_#{from}"
name = "temp_#{name}"
elsif from == "altered_#{to}"
name = name[5..-1]
end
to_column_names = columns(to).map { |c| c.name }
columns = index.columns.map {|c| rename[c] || c }.select do |column|
to_column_names.include?(column)
end
unless columns.empty?
# index name can't be the same
opts = { :name => name.gsub(/_(#{from})_/, "_#{to}_") }
opts[:unique] = true if index.unique
add_index(to, columns, opts)
end
end
end
def copy_table_contents(from, to, columns, rename = {}) #:nodoc:
column_mappings = Hash[columns.map {|name| [name, name]}]
rename.each { |a| column_mappings[a.last] = a.first }
from_columns = columns(from).collect {|col| col.name}
columns = columns.find_all{|col| from_columns.include?(column_mappings[col])}
quoted_columns = columns.map { |col| quote_column_name(col) } * ','
quoted_to = quote_table_name(to)
exec_query("SELECT * FROM #{quote_table_name(from)}").each do |row|
sql = "INSERT INTO #{quoted_to} (#{quoted_columns}) VALUES ("
sql << columns.map {|col| quote row[column_mappings[col]]} * ', '
sql << ')'
exec_query sql
end
end
def sqlite_version
@sqlite_version ||= SQLite3Adapter::Version.new(select_value('select sqlite_version(*)'))
end
def default_primary_key_type
if supports_autoincrement?
'INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL'
else
'INTEGER PRIMARY KEY NOT NULL'
end
end
def translate_exception(exception, message)
case exception.message
when /column(s)? .* (is|are) not unique/
RecordNotUnique.new(message, exception)
else
super
end
end
end
end
end