Module: ArJdbc::PostgreSQL

Included in:
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
Defined in:
lib/arjdbc/postgresql/adapter.rb

Defined Under Namespace

Modules: Column

Constant Summary collapse

ADAPTER_NAME =

constants taken from postgresql_adapter in rails project

'PostgreSQL'
NATIVE_DATABASE_TYPES = 
{
  :primary_key => "serial primary key",
  :string      => { :name => "character varying", :limit => 255 },
  :text        => { :name => "text" },
  :integer     => { :name => "integer" },
  :float       => { :name => "float" },
  :decimal     => { :name => "decimal" },
  :datetime    => { :name => "timestamp" },
  :timestamp   => { :name => "timestamp" },
  :time        => { :name => "time" },
  :date        => { :name => "date" },
  :binary      => { :name => "bytea" },
  :boolean     => { :name => "boolean" },
  :xml         => { :name => "xml" },
  :tsvector    => { :name => "tsvector" }
}

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.arel2_visitors(config) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 185

def self.arel2_visitors(config)
  {}.tap {|v| %w(postgresql pg jdbcpostgresql).each {|a| v[a] = ::Arel::Visitors::PostgreSQL } }
end

.column_selector ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 13

def self.column_selector
  [/postgre/i, lambda {|cfg,col| col.extend(::ArJdbc::PostgreSQL::Column)}]
end

.extended(mod) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 7

def self.extended(mod)
  (class << mod; self; end).class_eval do
    alias_chained_method :columns, :query_cache, :pg_columns
  end
end

.jdbc_connection_class ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 17

def self.jdbc_connection_class
  ::ActiveRecord::ConnectionAdapters::PostgresJdbcConnection
end

Instance Method Details

#adapter_name ⇒ Object

:nodoc:



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# File 'lib/arjdbc/postgresql/adapter.rb', line 181

def adapter_name #:nodoc:
  ADAPTER_NAME
end

#add_column(table_name, column_name, type, options = {}) ⇒ Object

Adds a new column to the named table. See TableDefinition#column for details of the options you can use.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 630

def add_column(table_name, column_name, type, options = {})
  default = options[:default]
  notnull = options[:null] == false

  # Add the column.
  execute("ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}")

  change_column_default(table_name, column_name, default) if options_include_default?(options)
  change_column_null(table_name, column_name, false, default) if notnull
end

#add_order_by_for_association_limiting!(sql, options) ⇒ Object

ORDER BY clause for the passed order option.

PostgreSQL does not allow arbitrary ordering when using DISTINCT ON, so we work around this by wrapping the sql as a sub-select and ordering in that query.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 545

def add_order_by_for_association_limiting!(sql, options)
  return sql if options[:order].blank?

  order = options[:order].split(',').collect { |s| s.strip }.reject(&:blank?)
  order.map! { |s| 'DESC' if s =~ /\bdesc$/i }
  order = order.zip((0...order.size).to_a).map { |s,i| "id_list.alias_#{i} #{s}" }.join(', ')

  sql.replace "SELECT * FROM (#{sql}) AS id_list ORDER BY #{order}"
end

#all_schemas ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 490

def all_schemas
  select('select nspname from pg_namespace').map {|r| r["nspname"] }
end

#change_column(table_name, column_name, type, options = {}) ⇒ Object

Changes the column of a table.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 642

def change_column(table_name, column_name, type, options = {})
  quoted_table_name = quote_table_name(table_name)

  begin
    execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
  rescue ActiveRecord::StatementInvalid => e
    raise e if postgresql_version > 80000
    # This is PostgreSQL 7.x, so we have to use a more arcane way of doing it.
    begin
      begin_db_transaction
      tmp_column_name = "#{column_name}_ar_tmp"
      add_column(table_name, tmp_column_name, type, options)
      execute "UPDATE #{quoted_table_name} SET #{quote_column_name(tmp_column_name)} = CAST(#{quote_column_name(column_name)} AS #{type_to_sql(type, options[:limit], options[:precision], options[:scale])})"
      remove_column(table_name, column_name)
      rename_column(table_name, tmp_column_name, column_name)
      commit_db_transaction
    rescue
      rollback_db_transaction
    end
  end

  change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
  change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
end

#change_column_default(table_name, column_name, default) ⇒ Object

Changes the default value of a table column.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 668

def change_column_default(table_name, column_name, default)
  execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote(default)}"
end

#change_column_null(table_name, column_name, null, default = nil) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 672

def change_column_null(table_name, column_name, null, default = nil)
  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end
  execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
end

#create_database(name, options = {}) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 474

def create_database(name, options = {})
  execute "CREATE DATABASE \"#{name}\" ENCODING='#{options[:encoding] || 'utf8'}'"
end

#create_savepoint ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 238

def create_savepoint
  execute("SAVEPOINT #{current_savepoint_name}")
end

#create_schema(schema_name, pg_username) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 482

def create_schema(schema_name, pg_username)
  execute("CREATE SCHEMA \"#{schema_name}\" AUTHORIZATION \"#{pg_username}\"")
end

#current_database ⇒ Object

current database name



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# File 'lib/arjdbc/postgresql/adapter.rb', line 392

def current_database
  exec_query("select current_database() as database").
    first["database"]
end

#default_sequence_name(table_name, pk = nil) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 256

def default_sequence_name(table_name, pk = nil)
  default_pk, default_seq = pk_and_sequence_for(table_name)
  default_seq || "#{table_name}_#{pk || default_pk || 'id'}_seq"
end

#disable_referential_integrity(&block) ⇒ Object

:nodoc:



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# File 'lib/arjdbc/postgresql/adapter.rb', line 617

def disable_referential_integrity(&block) #:nodoc:
  execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" }.join(";"))
  yield
ensure
  execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" }.join(";"))
end

#distinct(columns, orders) ⇒ Object

SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.

PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.

distinct("posts.id", "posts.created_at desc")



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# File 'lib/arjdbc/postgresql/adapter.rb', line 528

def distinct(columns, orders) #:nodoc:
  return "DISTINCT #{columns}" if orders.empty?

  # Construct a clean list of column names from the ORDER BY clause, removing
  # any ASC/DESC modifiers
  order_columns = orders.collect { |s| s.gsub(/\s+(ASC|DESC)\s*/i, '') }.
    reject(&:blank?)
  order_columns = order_columns.
    zip((0...order_columns.size).to_a).map { |s,i| "#{s} AS alias_#{i}" }

  "DISTINCT #{columns}, #{order_columns * ', '}"
end

#drop_database(name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 478

def drop_database(name)
  execute "DROP DATABASE IF EXISTS \"#{name}\""
end

#drop_schema(schema_name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 486

def drop_schema(schema_name)
  execute("DROP SCHEMA \"#{schema_name}\"")
end

#encoding ⇒ Object

current database encoding



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# File 'lib/arjdbc/postgresql/adapter.rb', line 398

def encoding
  exec_query("    SELECT pg_encoding_to_char(pg_database.encoding) as encoding\n    FROM pg_database\n    WHERE pg_database.datname LIKE '\#{current_database}'\n  end_sql\nend\n").first["encoding"]

#escape_bytea(s) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 586

def escape_bytea(s)
  if s
    result = ''
    s.each_byte { |c| result << sprintf('\\\\%03o', c) }
    result
  end
end

#extract_schema_and_table(name) ⇒ Object

Extracts the table and schema name from name



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# File 'lib/arjdbc/postgresql/adapter.rb', line 728

def extract_schema_and_table(name)
  schema, table = name.split('.', 2)

  unless table # A table was provided without a schema
    table  = schema
    schema = nil
  end

  if name =~ /^"/ # Handle quoted table names
    table  = name
    schema = nil
  end
  [schema, table]
end

#index_name_length ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 687

def index_name_length
  63
end

#indexes(table_name, name = nil) ⇒ Object

Based on postgresql_adapter.rb



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# File 'lib/arjdbc/postgresql/adapter.rb', line 417

def indexes(table_name, name = nil)
  schema_search_path = @config[:schema_search_path] || select_rows('SHOW search_path')[0][0]
  schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
  result = select_rows("    SELECT i.relname, d.indisunique, a.attname, a.attnum, d.indkey\n      FROM pg_class t, pg_class i, pg_index d, pg_attribute a,\n      generate_series(0,\#{multi_column_index_limit - 1}) AS s(i)\n     WHERE i.relkind = 'i'\n       AND d.indexrelid = i.oid\n       AND d.indisprimary = 'f'\n       AND t.oid = d.indrelid\n       AND t.relname = '\#{table_name}'\n       AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname IN (\#{schemas}) )\n       AND a.attrelid = t.oid\n       AND d.indkey[s.i]=a.attnum\n    ORDER BY i.relname\n  SQL\n\n  current_index = nil\n  indexes = []\n\n  insertion_order = []\n  index_order = nil\n\n  result.each do |row|\n    if current_index != row[0]\n\n      (index_order = row[4].split(' ')).each_with_index{ |v, i| index_order[i] = v.to_i }\n      indexes << ::ActiveRecord::ConnectionAdapters::IndexDefinition.new(table_name, row[0], row[1] == \"t\", [])\n      current_index = row[0]\n    end\n    insertion_order = row[3]\n    ind = index_order.index(insertion_order)\n    indexes.last.columns[ind] = row[2]\n  end\n\n  indexes\nend\n", name)

#insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = []) ⇒ Object

Insert logic for pre-AR-3.1 adapters



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# File 'lib/arjdbc/postgresql/adapter.rb', line 330

def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [])
  # Extract the table from the insert sql. Yuck.
  table = sql.split(" ", 4)[2].gsub('"', '')

  # Try an insert with 'returning id' if available (PG >= 8.2)
  if supports_insert_with_returning? && id_value.nil?
    pk, sequence_name = *pk_and_sequence_for(table) unless pk
    if pk
      sql = substitute_binds(sql, binds)
      id_value = select_value("#{sql} RETURNING #{quote_column_name(pk)}")
      clear_query_cache #FIXME: Why now?
      return id_value
    end
  end

  # Otherwise, plain insert
  execute(sql, name, binds)

  # Don't need to look up id_value if we already have it.
  # (and can't in case of non-sequence PK)
  unless id_value
    # If neither pk nor sequence name is given, look them up.
    unless pk || sequence_name
      pk, sequence_name = *pk_and_sequence_for(table)
    end

    # If a pk is given, fallback to default sequence name.
    # Don't fetch last insert id for a table without a pk.
    if pk && sequence_name ||= default_sequence_name(table, pk)
      id_value = last_insert_id(table, sequence_name)
    end
  end
  id_value
end

#last_insert_id(table, sequence_name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 465

def last_insert_id(table, sequence_name)
  Integer(select_value("SELECT currval('#{sequence_name}')"))
end

#last_inserted_id(result) ⇒ Object

take id from result of insert query



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# File 'lib/arjdbc/postgresql/adapter.rb', line 457

def last_inserted_id(result)
  if result.is_a? Fixnum
    result
  else
    result.first.first[1]
  end
end

#multi_column_index_limit ⇒ Object

Gets the maximum number columns postgres has, default 32



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# File 'lib/arjdbc/postgresql/adapter.rb', line 412

def multi_column_index_limit
  defined?(@multi_column_index_limit) && @multi_column_index_limit || 32
end

#multi_column_index_limit=(limit) ⇒ Object

Sets the maximum number columns postgres has, default 32



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# File 'lib/arjdbc/postgresql/adapter.rb', line 407

def multi_column_index_limit=(limit)
  @multi_column_index_limit = limit
end

#native_database_types ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 201

def native_database_types
  NATIVE_DATABASE_TYPES
end

#pg_columns(table_name, name = nil) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 383

def pg_columns(table_name, name=nil)
  column_definitions(table_name).map do |row|
    ::ActiveRecord::ConnectionAdapters::PostgreSQLColumn.new(
      row["column_name"], row["column_default"], row["column_type"],
      row["column_not_null"] == "f")
  end
end

#pk_and_sequence_for(table) ⇒ Object

Find a table’s primary key and sequence.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 282

def pk_and_sequence_for(table) #:nodoc:
  # First try looking for a sequence with a dependency on the
  # given table's primary key.
  result = select("      SELECT attr.attname, seq.relname\n      FROM pg_class      seq,\n           pg_attribute  attr,\n           pg_depend     dep,\n           pg_namespace  name,\n           pg_constraint cons\n      WHERE seq.oid           = dep.objid\n        AND seq.relkind       = 'S'\n        AND attr.attrelid     = dep.refobjid\n        AND attr.attnum       = dep.refobjsubid\n        AND attr.attrelid     = cons.conrelid\n        AND attr.attnum       = cons.conkey[1]\n        AND cons.contype      = 'p'\n        AND dep.refobjid      = '\#{quote_table_name(table)}'::regclass\n    end_sql\n\n  if result.nil? or result.empty?\n    # If that fails, try parsing the primary key's default value.\n    # Support the 7.x and 8.0 nextval('foo'::text) as well as\n    # the 8.1+ nextval('foo'::regclass).\n    result = select(<<-end_sql, 'PK and custom sequence')[0]\n        SELECT attr.attname,\n          CASE\n            WHEN split_part(def.adsrc, '''', 2) ~ '.' THEN\n              substr(split_part(def.adsrc, '''', 2),\n                     strpos(split_part(def.adsrc, '''', 2), '.')+1)\n            ELSE split_part(def.adsrc, '''', 2)\n          END as relname\n        FROM pg_class       t\n        JOIN pg_attribute   attr ON (t.oid = attrelid)\n        JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)\n        JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])\n        WHERE t.oid = '\#{quote_table_name(table)}'::regclass\n          AND cons.contype = 'p'\n          AND def.adsrc ~* 'nextval'\n      end_sql\n  end\n\n  [result[\"attname\"], result[\"relname\"]]\nrescue\n  nil\nend\n", 'PK and serial sequence')[0]

#postgresql_version ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 189

def postgresql_version
  @postgresql_version ||=
    begin
      value = select_value('SELECT version()')
      if value =~ /PostgreSQL (\d+)\.(\d+)\.(\d+)/
        ($1.to_i * 10000) + ($2.to_i * 100) + $3.to_i
      else
        0
      end
    end
end

#primary_key(table) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 365

def primary_key(table)
  pk_and_sequence = pk_and_sequence_for(table)
  pk_and_sequence && pk_and_sequence.first
end

#quote(value, column = nil) ⇒ Object

from postgres_adapter.rb in rails project github.com/rails/rails/blob/3-1-stable/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb#L412 Quotes PostgreSQL-specific data types for SQL input.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 558

def quote(value, column = nil) #:nodoc:
  return super unless column

  case value
  when Float
    return super unless value.infinite? && column.type == :datetime
    "'#{value.to_s.downcase}'"
  when Numeric
    return super unless column.sql_type == 'money'
    # Not truly string input, so doesn't require (or allow) escape string syntax.
    "'#{value}'"
  when String
    case column.sql_type
    when 'bytea' then "'#{escape_bytea(value)}'"
    when 'xml'   then "xml '#{quote_string(value)}'"
    when /^bit/
      case value
      when /^[01]*$/      then "B'#{value}'" # Bit-string notation
      when /^[0-9A-F]*$/i then "X'#{value}'" # Hexadecimal notation
      end
    else
      super
    end
  else
    super
  end
end

#quote_column_name(name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 605

def quote_column_name(name)
  %("#{name.to_s.gsub("\"", "\"\"")}")
end

#quote_table_name(name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 594

def quote_table_name(name)
  schema, name_part = extract_pg_identifier_from_name(name.to_s)

  unless name_part
    quote_column_name(schema)
  else
    table_name, name_part = extract_pg_identifier_from_name(name_part)
    "#{quote_column_name(schema)}.#{quote_column_name(table_name)}"
  end
end

#quoted_date(value) ⇒ Object

:nodoc:



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# File 'lib/arjdbc/postgresql/adapter.rb', line 609

def quoted_date(value) #:nodoc:
  if value.acts_like?(:time) && value.respond_to?(:usec)
    "#{super}.#{sprintf("%06d", value.usec)}"
  else
    super
  end
end

#recreate_database(name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 469

def recreate_database(name)
  drop_database(name)
  create_database(name)
end

#release_savepoint ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 246

def release_savepoint
  execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end

#remove_index!(table_name, index_name) ⇒ Object

:nodoc:



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# File 'lib/arjdbc/postgresql/adapter.rb', line 683

def remove_index!(table_name, index_name) #:nodoc:
  execute "DROP INDEX #{quote_table_name(index_name)}"
end

#rename_column(table_name, column_name, new_column_name) ⇒ Object

:nodoc:



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# File 'lib/arjdbc/postgresql/adapter.rb', line 679

def rename_column(table_name, column_name, new_column_name) #:nodoc:
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
end

#rename_table(name, new_name) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 624

def rename_table(name, new_name)
  execute "ALTER TABLE #{name} RENAME TO #{new_name}"
end

#reset_pk_sequence!(table, pk = nil, sequence = nil) ⇒ Object

Resets sequence to the max value of the table’s pk if present.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 262

def reset_pk_sequence!(table, pk = nil, sequence = nil) #:nodoc:
  unless pk and sequence
    default_pk, default_sequence = pk_and_sequence_for(table)
    pk ||= default_pk
    sequence ||= default_sequence
  end
  if pk
    if sequence
      quoted_sequence = quote_column_name(sequence)

      select_value "          SELECT setval('\#{quoted_sequence}', (SELECT COALESCE(MAX(\#{quote_column_name pk})+(SELECT increment_by FROM \#{quoted_sequence}), (SELECT min_value FROM \#{quoted_sequence})) FROM \#{quote_table_name(table)}), false)\n        end_sql\n    else\n      @logger.warn \"\#{table} has primary key \#{pk} with no default sequence\" if @logger\n    end\n  end\nend\n", 'Reset sequence'

#rollback_to_savepoint ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 242

def rollback_to_savepoint
  execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end

#sql_for_insert(sql, pk, id_value, sequence_name, binds) ⇒ Object

taken from rails postgresql adapter github.com/gfmurphy/rails/blob/master/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb#L611



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# File 'lib/arjdbc/postgresql/adapter.rb', line 372

def sql_for_insert(sql, pk, id_value, sequence_name, binds)
  unless pk
    table_ref = extract_table_ref_from_insert_sql(sql)
    pk = primary_key(table_ref) if table_ref
  end

  sql = "#{sql} RETURNING #{quote_column_name(pk)}" if pk

  [sql, binds]
end

#structure_dump ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 494

def structure_dump
  database = @config[:database]
  if database.nil?
    if @config[:url] =~ /\/([^\/]*)$/
      database = $1
    else
      raise "Could not figure out what database this url is for #{@config["url"]}"
    end
  end

  ENV['PGHOST']     = @config[:host] if @config[:host]
  ENV['PGPORT']     = @config[:port].to_s if @config[:port]
  ENV['PGPASSWORD'] = @config[:password].to_s if @config[:password]
  search_path = @config[:schema_search_path]
  search_path = "--schema=#{search_path}" if search_path

  @connection.connection.close
  begin
    definition = `pg_dump -i -U "#{@config[:username]}" -s -x -O #{search_path} #{database}`
    raise "Error dumping database" if $?.exitstatus == 1

    # need to patch away any references to SQL_ASCII as it breaks the JDBC driver
    definition.gsub(/SQL_ASCII/, 'UNICODE')
  ensure
    reconnect!
  end
end

#supports_ddl_transactions? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/postgresql/adapter.rb', line 230

def supports_ddl_transactions?
  true
end

#supports_insert_with_returning? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/postgresql/adapter.rb', line 226

def supports_insert_with_returning?
  postgresql_version >= 80200
end

#supports_migrations? ⇒ Boolean

Does PostgreSQL support migrations?

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/postgresql/adapter.rb', line 206

def supports_migrations?
  true
end

#supports_savepoints? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/postgresql/adapter.rb', line 234

def supports_savepoints?
  true
end

#supports_standard_conforming_strings? ⇒ Boolean

Does PostgreSQL support standard conforming strings?

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/postgresql/adapter.rb', line 211

def supports_standard_conforming_strings?
  # Temporarily set the client message level above error to prevent unintentional
  # error messages in the logs when working on a PostgreSQL database server that
  # does not support standard conforming strings.
  client_min_messages_old = client_min_messages
  self.client_min_messages = 'panic'

  # postgres-pr does not raise an exception when client_min_messages is set higher
  # than error and "SHOW standard_conforming_strings" fails, but returns an empty
  # PGresult instead.
  has_support = select('SHOW standard_conforming_strings').to_a[0][0] rescue false
  self.client_min_messages = client_min_messages_old
  has_support
end

#table_alias_length ⇒ Object

Returns the configured supported identifier length supported by PostgreSQL, or report the default of 63 on PostgreSQL 7.x.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 252

def table_alias_length
  @table_alias_length ||= (postgresql_version >= 80000 ? select_one('SHOW max_identifier_length')['max_identifier_length'].to_i : 63)
end

#table_exists?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arjdbc/postgresql/adapter.rb', line 712

def table_exists?(name)
  schema, table = extract_schema_and_table(name.to_s)
  return false unless table # Abstract classes is having nil table name

  binds = [[nil, table.gsub(/(^"|"$)/,'')]]
  binds << [nil, schema] if schema

  exec_query("      SELECT COUNT(*) as table_count\n      FROM pg_tables\n      WHERE tablename = ?\n      AND schemaname = \#{schema ? \"?\" : \"ANY (current_schemas(false))\"}\n  SQL\nend\n", 'SCHEMA', binds).first["table_count"] > 0

#tables(name = nil) ⇒ Object 



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# File 'lib/arjdbc/postgresql/adapter.rb', line 704

def tables(name = nil)
  exec_query("      SELECT tablename\n      FROM pg_tables\n      WHERE schemaname = ANY (current_schemas(false))\n  SQL\nend\n", 'SCHEMA').map { |row| row["tablename"] }

#type_to_sql(type, limit = nil, precision = nil, scale = nil) ⇒ Object

Maps logical Rails types to PostgreSQL-specific data types.



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# File 'lib/arjdbc/postgresql/adapter.rb', line 692

def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  return super unless type.to_s == 'integer'
  return 'integer' unless limit

  case limit
  when 1, 2; 'smallint'
  when 3, 4; 'integer'
  when 5..8; 'bigint'
  else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.")
  end
end