Class: Sequel::Postgres::Dataset
- Includes:
- DatasetMethods
- Defined in:
- lib/sequel/adapters/postgres.rb
Overview
Dataset class for PostgreSQL datasets that use the pg, postgres, or postgres-pr driver.
Defined Under Namespace
Modules: ArgumentMapper, BindArgumentMethods, PreparedStatementMethods
Constant Summary collapse
- PREPARED_ARG_PLACEHOLDER =
LiteralString.new('$').freeze
Constants included from DatasetMethods
Sequel::Postgres::DatasetMethods::ACCESS_EXCLUSIVE, Sequel::Postgres::DatasetMethods::ACCESS_SHARE, Sequel::Postgres::DatasetMethods::BOOL_FALSE, Sequel::Postgres::DatasetMethods::BOOL_TRUE, Sequel::Postgres::DatasetMethods::COMMA_SEPARATOR, Sequel::Postgres::DatasetMethods::DELETE_CLAUSE_METHODS, Sequel::Postgres::DatasetMethods::EXCLUSIVE, Sequel::Postgres::DatasetMethods::EXPLAIN, Sequel::Postgres::DatasetMethods::EXPLAIN_ANALYZE, Sequel::Postgres::DatasetMethods::FOR_SHARE, Sequel::Postgres::DatasetMethods::LOCK, Sequel::Postgres::DatasetMethods::NULL, Sequel::Postgres::DatasetMethods::PG_TIMESTAMP_FORMAT, Sequel::Postgres::DatasetMethods::QUERY_PLAN, Sequel::Postgres::DatasetMethods::ROW_EXCLUSIVE, Sequel::Postgres::DatasetMethods::ROW_SHARE, Sequel::Postgres::DatasetMethods::SELECT_CLAUSE_METHODS, Sequel::Postgres::DatasetMethods::SELECT_CLAUSE_METHODS_84, Sequel::Postgres::DatasetMethods::SHARE, Sequel::Postgres::DatasetMethods::SHARE_ROW_EXCLUSIVE, Sequel::Postgres::DatasetMethods::SHARE_UPDATE_EXCLUSIVE, Sequel::Postgres::DatasetMethods::SQL_WITH_RECURSIVE, Sequel::Postgres::DatasetMethods::UPDATE_CLAUSE_METHODS
Constants inherited from Dataset
Dataset::ACTION_METHODS, Dataset::AND_SEPARATOR, Dataset::ARG_BLOCK_ERROR_MSG, Dataset::ARRAY_ACCESS_ERROR_MSG, Dataset::BOOL_FALSE, Dataset::BOOL_TRUE, Dataset::COLUMN_CHANGE_OPTS, Dataset::COLUMN_REF_RE1, Dataset::COLUMN_REF_RE2, Dataset::COLUMN_REF_RE3, Dataset::COMMA_SEPARATOR, Dataset::CONDITIONED_JOIN_TYPES, Dataset::COUNT_FROM_SELF_OPTS, Dataset::COUNT_OF_ALL_AS_COUNT, Dataset::DATASET_ALIAS_BASE_NAME, Dataset::DELETE_CLAUSE_METHODS, Dataset::FOR_UPDATE, Dataset::IMPORT_ERROR_MSG, Dataset::INSERT_CLAUSE_METHODS, Dataset::IS_LITERALS, Dataset::IS_OPERATORS, Dataset::JOIN_METHODS, Dataset::MUTATION_METHODS, Dataset::NON_SQL_OPTIONS, Dataset::NOTIMPL_MSG, Dataset::NULL, Dataset::N_ARITY_OPERATORS, Dataset::QUALIFY_KEYS, Dataset::QUERY_METHODS, Dataset::QUESTION_MARK, Dataset::SELECT_CLAUSE_METHODS, Dataset::SQL_WITH, Dataset::STANDARD_TIMESTAMP_FORMAT, Dataset::TIMESTAMP_FORMAT, Dataset::TWO_ARITY_OPERATORS, Dataset::UNCONDITIONED_JOIN_TYPES, Dataset::UPDATE_CLAUSE_METHODS, Dataset::WILDCARD, Dataset::WITH_SUPPORTED
Instance Attribute Summary
Attributes inherited from Dataset
#db, #identifier_input_method, #identifier_output_method, #opts, #quote_identifiers, #row_proc
Instance Method Summary collapse
-
#call(type, bind_vars = {}, *values, &block) ⇒ Object
Execute the given type of statement with the hash of values.
-
#fetch_rows(sql, &block) ⇒ Object
Yield all rows returned by executing the given SQL and converting the types.
-
#prepare(type, name = nil, *values) ⇒ Object
Prepare the given type of statement with the given name, and store it in the database to be called later.
-
#use_cursor(opts = {}) ⇒ Object
Uses a cursor for fetching records, instead of fetching the entire result set at once.
Methods included from DatasetMethods
#analyze, #complex_expression_sql, #disable_insert_returning, #explain, extended, #for_share, #full_text_search, included, #insert, #insert_returning_sql, #insert_select, #lock, #multi_insert_sql, #supports_distinct_on?, #supports_modifying_joins?, #supports_timestamp_timezones?, #supports_window_functions?, #window
Methods inherited from Dataset
#<<, #==, #[], #[]=, #add_graph_aliases, #aliased_expression_sql, #all, #and, #array_sql, #as, #avg, #bind, #boolean_constant_sql, #case_expression_sql, #cast_sql, clause_methods, #clone, #column_all_sql, #columns, #columns!, #complex_expression_sql, #constant_sql, #count, def_mutation_method, #def_mutation_method, #delete, #delete_sql, #distinct, #each, #each_page, #each_server, #empty?, #eql?, #except, #exclude, #exists, #filter, #first, #first_source, #first_source_alias, #first_source_table, #for_update, #from, #from_self, #function_sql, #get, #graph, #grep, #group, #group_and_count, #group_by, #hash, #having, #import, #initialize, #insert, #insert_multiple, #insert_sql, #inspect, #intersect, #interval, #invert, #join, #join_clause_sql, #join_on_clause_sql, #join_table, #join_using_clause_sql, #last, #limit, #literal, #lock_style, #map, #max, #min, #multi_insert, #multi_insert_sql, #naked, #negative_boolean_constant_sql, #or, #order, #order_append, #order_by, #order_more, #order_prepend, #ordered_expression_sql, #paginate, #placeholder_literal_string_sql, #print, #provides_accurate_rows_matched?, #qualified_identifier_sql, #qualify, #qualify_to, #qualify_to_first_source, #query, #quote_identifier, #quote_identifiers?, #quote_schema_table, #quoted_identifier, #range, #requires_sql_standard_datetimes?, #reverse, #reverse_order, #schema_and_table, #select, #select_all, #select_append, #select_hash, #select_map, #select_more, #select_order_map, #select_sql, #server, #set, #set_defaults, #set_graph_aliases, #set_overrides, #single_record, #single_value, #split_alias, #sql, #subscript_sql, #sum, #supports_cte?, #supports_distinct_on?, #supports_intersect_except?, #supports_intersect_except_all?, #supports_is_true?, #supports_join_using?, #supports_modifying_joins?, #supports_multiple_column_in?, #supports_timestamp_timezones?, #supports_timestamp_usecs?, #supports_window_functions?, #to_csv, #to_hash, #truncate, #truncate_sql, #unfiltered, #ungraphed, #ungrouped, #union, #unlimited, #unordered, #unused_table_alias, #update, #update_sql, #where, #window_function_sql, #window_sql, #with, #with_recursive, #with_sql
Methods included from Metaprogramming
Constructor Details
This class inherits a constructor from Sequel::Dataset
Instance Method Details
#call(type, bind_vars = {}, *values, &block) ⇒ Object
Execute the given type of statement with the hash of values.
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# File 'lib/sequel/adapters/postgres.rb', line 412 def call(type, bind_vars={}, *values, &block) ps = to_prepared_statement(type, values) ps.extend(BindArgumentMethods) ps.call(bind_vars, &block) end |
#fetch_rows(sql, &block) ⇒ Object
Yield all rows returned by executing the given SQL and converting the types.
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# File 'lib/sequel/adapters/postgres.rb', line 304 def fetch_rows(sql, &block) return cursor_fetch_rows(sql, &block) if @opts[:cursor] execute(sql){|res| yield_hash_rows(res, fetch_rows_set_cols(res), &block)} end |
#prepare(type, name = nil, *values) ⇒ Object
Prepare the given type of statement with the given name, and store it in the database to be called later.
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# File 'lib/sequel/adapters/postgres.rb', line 420 def prepare(type, name=nil, *values) ps = to_prepared_statement(type, values) ps.extend(PreparedStatementMethods) if name ps.prepared_statement_name = name db.prepared_statements[name] = ps end ps end |
#use_cursor(opts = {}) ⇒ Object
Uses a cursor for fetching records, instead of fetching the entire result set at once. Can be used to process large datasets without holding all rows in memory (which is what the underlying drivers do by default). Options:
-
:rows_per_fetch - the number of rows per fetch (default 1000). Higher numbers result in fewer queries but greater memory use.
Usage:
DB[:huge_table].use_cursor.each{|row| p row}
DB[:huge_table].use_cursor(:rows_per_fetch=>10000).each{|row| p row}
This is untested with the prepared statement/bound variable support, and unlikely to work with either.
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# File 'lib/sequel/adapters/postgres.rb', line 324 def use_cursor(opts={}) clone(:cursor=>{:rows_per_fetch=>1000}.merge(opts)) end |