Module: Sequel::Postgres::DatabaseMethods
- Defined in:
- lib/sequel/adapters/shared/postgres.rb
Overview
Methods shared by Database instances that connect to PostgreSQL.
Constant Summary collapse
- EXCLUDE_SCHEMAS =
/pg_*|information_schema/i
- PREPARED_ARG_PLACEHOLDER =
LiteralString.new('$').freeze
- RE_CURRVAL_ERROR =
/currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.freeze
- SYSTEM_TABLE_REGEXP =
/^pg|sql/.freeze
Instance Method Summary collapse
-
#commit_prepared_transaction(transaction_id) ⇒ Object
Commit an existing prepared transaction with the given transaction identifier string.
-
#create_function(name, definition, opts = {}) ⇒ Object
Creates the function in the database.
-
#create_language(name, opts = {}) ⇒ Object
Create the procedural language in the database.
-
#create_trigger(table, name, function, opts = {}) ⇒ Object
Create a trigger in the database.
-
#database_type ⇒ Object
PostgreSQL uses the :postgres database type.
-
#drop_function(name, opts = {}) ⇒ Object
Drops the function from the database.
-
#drop_language(name, opts = {}) ⇒ Object
Drops a procedural language from the database.
-
#drop_table(*names) ⇒ Object
Remove the cached entries for primary keys and sequences when dropping a table.
-
#drop_trigger(table, name, opts = {}) ⇒ Object
Drops a trigger from the database.
-
#indexes(table, opts = {}) ⇒ Object
Use the pg_* system tables to determine indexes on a table.
-
#locks ⇒ Object
Dataset containing all current database locks.
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#primary_key(table, opts = {}) ⇒ Object
Return primary key for the given table.
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#primary_key_sequence(table, opts = {}) ⇒ Object
Return the sequence providing the default for the primary key for the given table.
-
#reset_primary_key_sequence(table) ⇒ Object
Reset the primary key sequence for the given table, baseing it on the maximum current value of the table’s primary key.
-
#rollback_prepared_transaction(transaction_id) ⇒ Object
Rollback an existing prepared transaction with the given transaction identifier string.
-
#serial_primary_key_options ⇒ Object
PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for managing incrementing primary keys.
-
#server_version(server = nil) ⇒ Object
The version of the PostgreSQL server, used for determining capability.
-
#supports_prepared_transactions? ⇒ Boolean
PostgreSQL supports prepared transactions (two-phase commit) if max_prepared_transactions is greater than 0.
-
#supports_savepoints? ⇒ Boolean
PostgreSQL supports savepoints.
-
#supports_transaction_isolation_levels? ⇒ Boolean
PostgreSQL supports transaction isolation levels.
-
#table_exists?(table, opts = {}) ⇒ Boolean
Whether the given table exists in the database.
-
#tables(opts = {}) ⇒ Object
Array of symbols specifying table names in the current database.
Instance Method Details
#commit_prepared_transaction(transaction_id) ⇒ Object
Commit an existing prepared transaction with the given transaction identifier string.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 167 def commit_prepared_transaction(transaction_id) run("COMMIT PREPARED #{literal(transaction_id)}") end |
#create_function(name, definition, opts = {}) ⇒ Object
Creates the function in the database. Arguments:
-
name : name of the function to create
-
definition : string definition of the function, or object file for a dynamically loaded C function.
-
opts : options hash:
-
:args : function arguments, can be either a symbol or string specifying a type or an array of 1-3 elements:
-
element 1 : argument data type
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element 2 : argument name
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element 3 : argument mode (e.g. in, out, inout)
-
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:behavior : Should be IMMUTABLE, STABLE, or VOLATILE. PostgreSQL assumes VOLATILE by default.
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:cost : The estimated cost of the function, used by the query planner.
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:language : The language the function uses. SQL is the default.
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:link_symbol : For a dynamically loaded see function, the function’s link symbol if different from the definition argument.
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:returns : The data type returned by the function. If you are using OUT or INOUT argument modes, this is ignored. Otherwise, if this is not specified, void is used by default to specify the function is not supposed to return a value.
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:rows : The estimated number of rows the function will return. Only use if the function returns SETOF something.
-
:security_definer : Makes the privileges of the function the same as the privileges of the user who defined the function instead of the privileges of the user who runs the function. There are security implications when doing this, see the PostgreSQL documentation.
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:set : Configuration variables to set while the function is being run, can be a hash or an array of two pairs. search_path is often used here if :security_definer is used.
-
:strict : Makes the function return NULL when any argument is NULL.
-
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# File 'lib/sequel/adapters/shared/postgres.rb', line 191 def create_function(name, definition, opts={}) self << create_function_sql(name, definition, opts) end |
#create_language(name, opts = {}) ⇒ Object
Create the procedural language in the database. Arguments:
-
name : Name of the procedural language (e.g. plpgsql)
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opts : options hash:
-
:handler : The name of a previously registered function used as a call handler for this language.
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:trusted : Marks the language being created as trusted, allowing unprivileged users to create functions using this language.
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:validator : The name of previously registered function used as a validator of functions defined in this language.
-
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# File 'lib/sequel/adapters/shared/postgres.rb', line 201 def create_language(name, opts={}) self << create_language_sql(name, opts) end |
#create_trigger(table, name, function, opts = {}) ⇒ Object
Create a trigger in the database. Arguments:
-
table : the table on which this trigger operates
-
name : the name of this trigger
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function : the function to call for this trigger, which should return type trigger.
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opts : options hash:
-
:after : Calls the trigger after execution instead of before.
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:args : An argument or array of arguments to pass to the function.
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:each_row : Calls the trigger for each row instead of for each statement.
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:events : Can be :insert, :update, :delete, or an array of any of those. Calls the trigger whenever that type of statement is used. By default, the trigger is called for insert, update, or delete.
-
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# File 'lib/sequel/adapters/shared/postgres.rb', line 215 def create_trigger(table, name, function, opts={}) self << create_trigger_sql(table, name, function, opts) end |
#database_type ⇒ Object
PostgreSQL uses the :postgres database type.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 220 def database_type :postgres end |
#drop_function(name, opts = {}) ⇒ Object
Drops the function from the database. Arguments:
-
name : name of the function to drop
-
opts : options hash:
-
:args : The arguments for the function. See create_function_sql.
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:cascade : Drop other objects depending on this function.
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:if_exists : Don’t raise an error if the function doesn’t exist.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 230 def drop_function(name, opts={}) self << drop_function_sql(name, opts) end |
#drop_language(name, opts = {}) ⇒ Object
Drops a procedural language from the database. Arguments:
-
name : name of the procedural language to drop
-
opts : options hash:
-
:cascade : Drop other objects depending on this function.
-
:if_exists : Don’t raise an error if the function doesn’t exist.
-
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# File 'lib/sequel/adapters/shared/postgres.rb', line 239 def drop_language(name, opts={}) self << drop_language_sql(name, opts) end |
#drop_table(*names) ⇒ Object
Remove the cached entries for primary keys and sequences when dropping a table.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 244 def drop_table(*names) names.each do |name| name = quote_schema_table(name) @primary_keys.delete(name) @primary_key_sequences.delete(name) end super end |
#drop_trigger(table, name, opts = {}) ⇒ Object
Drops a trigger from the database. Arguments:
-
table : table from which to drop the trigger
-
name : name of the trigger to drop
-
opts : options hash:
-
:cascade : Drop other objects depending on this function.
-
:if_exists : Don’t raise an error if the function doesn’t exist.
-
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# File 'lib/sequel/adapters/shared/postgres.rb', line 259 def drop_trigger(table, name, opts={}) self << drop_trigger_sql(table, name, opts) end |
#indexes(table, opts = {}) ⇒ Object
Use the pg_* system tables to determine indexes on a table
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# File 'lib/sequel/adapters/shared/postgres.rb', line 264 def indexes(table, opts={}) m = output_identifier_meth im = input_identifier_meth schema, table = schema_and_table(table) range = 0...32 attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])} ds = . from(:pg_class___tab). join(:pg_index___ind, :indrelid=>:oid, im.call(table)=>:relname). join(:pg_class___indc, :oid=>:indexrelid). join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums). filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil). order(:indc__relname, range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}.case(32, :att__attnum)). select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column) ds.join!(:pg_namespace___nsp, :oid=>:tab__relnamespace, :nspname=>schema.to_s) if schema ds.filter!(:indisvalid=>true) if server_version >= 80200 ds.filter!(:indisready=>true, :indcheckxmin=>false) if server_version >= 80300 indexes = {} ds.each do |r| i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique]} i[:columns] << m.call(r[:column]) end indexes end |
#locks ⇒ Object
Dataset containing all current database locks
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# File 'lib/sequel/adapters/shared/postgres.rb', line 292 def locks dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks)) end |
#primary_key(table, opts = {}) ⇒ Object
Return primary key for the given table.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 297 def primary_key(table, opts={}) quoted_table = quote_schema_table(table) return @primary_keys[quoted_table] if @primary_keys.include?(quoted_table) @primary_keys[quoted_table] = if conn = opts[:conn] conn.primary_key(*schema_and_table(table)) else synchronize(opts[:server]){|con| con.primary_key(*schema_and_table(table))} end end |
#primary_key_sequence(table, opts = {}) ⇒ Object
Return the sequence providing the default for the primary key for the given table.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 308 def primary_key_sequence(table, opts={}) quoted_table = quote_schema_table(table) return @primary_key_sequences[quoted_table] if @primary_key_sequences.include?(quoted_table) @primary_key_sequences[quoted_table] = if conn = opts[:conn] conn.sequence(*schema_and_table(table)) else synchronize(opts[:server]){|con| con.sequence(*schema_and_table(table))} end end |
#reset_primary_key_sequence(table) ⇒ Object
Reset the primary key sequence for the given table, baseing it on the maximum current value of the table’s primary key.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 320 def reset_primary_key_sequence(table) pk = SQL::Identifier.new(primary_key(table)) return unless seq = primary_key_sequence(table) db = self seq_ds = db.from(seq.lit) get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)} end |
#rollback_prepared_transaction(transaction_id) ⇒ Object
Rollback an existing prepared transaction with the given transaction identifier string.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 330 def rollback_prepared_transaction(transaction_id) run("ROLLBACK PREPARED #{literal(transaction_id)}") end |
#serial_primary_key_options ⇒ Object
PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for managing incrementing primary keys.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 336 def {:primary_key => true, :serial => true, :type=>Integer} end |
#server_version(server = nil) ⇒ Object
The version of the PostgreSQL server, used for determining capability.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 341 def server_version(server=nil) return @server_version if @server_version @server_version = synchronize(server) do |conn| (conn.server_version rescue nil) if conn.respond_to?(:server_version) end unless @server_version m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value) @server_version = (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i end @server_version end |
#supports_prepared_transactions? ⇒ Boolean
PostgreSQL supports prepared transactions (two-phase commit) if max_prepared_transactions is greater than 0.
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# File 'lib/sequel/adapters/shared/postgres.rb', line 355 def supports_prepared_transactions? return @supports_prepared_transactions if defined?(@supports_prepared_transactions) @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0 end |
#supports_savepoints? ⇒ Boolean
PostgreSQL supports savepoints
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# File 'lib/sequel/adapters/shared/postgres.rb', line 361 def supports_savepoints? true end |
#supports_transaction_isolation_levels? ⇒ Boolean
PostgreSQL supports transaction isolation levels
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# File 'lib/sequel/adapters/shared/postgres.rb', line 366 def supports_transaction_isolation_levels? true end |
#table_exists?(table, opts = {}) ⇒ Boolean
Whether the given table exists in the database
Options:
-
:schema - The schema to search (default_schema by default)
-
:server - The server to use
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# File 'lib/sequel/adapters/shared/postgres.rb', line 375 def table_exists?(table, opts={}) im = input_identifier_meth schema, table = schema_and_table(table) opts[:schema] ||= schema tables(opts){|ds| !ds.first(:relname=>im.call(table)).nil?} end |
#tables(opts = {}) ⇒ Object
Array of symbols specifying table names in the current database. The dataset used is yielded to the block if one is provided, otherwise, an array of symbols of table names is returned.
Options:
-
:schema - The schema to search (default_schema by default)
-
:server - The server to use
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# File 'lib/sequel/adapters/shared/postgres.rb', line 389 def tables(opts={}) ds = .from(:pg_class).filter(:relkind=>'r').select(:relname).exclude(SQL::StringExpression.like(:relname, SYSTEM_TABLE_REGEXP)).server(opts[:server]).join(:pg_namespace, :oid=>:relnamespace) ds = filter_schema(ds, opts) m = output_identifier_meth block_given? ? yield(ds) : ds.map{|r| m.call(r[:relname])} end |