ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

add_exclusion_constraint(table_name, expression, **options) 链接

向表中添加新的排他约束。expression 是 String 表示的排他元素和操作符列表。

add_exclusion_constraint :products, "price WITH =, availability_range WITH &&", using: :gist, name: "price_check"

生成

ALTER TABLE "products" ADD CONSTRAINT price_check EXCLUDE USING gist (price WITH =, availability_range WITH &&)

options 哈希可以包含以下键

:name: 约束名称。默认为 excl_rails_<identifier>。
:deferrable: 指定排他约束是否应为可延迟的。有效值为 false 或 :immediate 或 :deferred 用于指定默认行为。默认为 false。
:using: 指定创建此排他约束时要使用的索引方法（例如 :btree、:gist 等）。
:where: 指定对表子集的排他约束（在内部，PostgreSQL 为此创建部分索引）。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 745
def add_exclusion_constraint(table_name, expression, **options)
  options = exclusion_constraint_options(table_name, expression, options)
  at = create_alter_table(table_name)
  at.add_exclusion_constraint(expression, options)

  execute schema_creation.accept(at)
end

add_foreign_key(from_table, to_table, **options) 链接

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 578
def add_foreign_key(from_table, to_table, **options)
  assert_valid_deferrable(options[:deferrable])

  super
end

add_unique_constraint(table_name, column_name = nil, **options) 链接

向表中添加新的唯一约束。

add_unique_constraint :sections, [:position], deferrable: :deferred, name: "unique_position", nulls_not_distinct: true

生成

ALTER TABLE "sections" ADD CONSTRAINT unique_position UNIQUE (position) DEFERRABLE INITIALLY DEFERRED

如果要将现有的唯一索引更改为可延迟的，可以使用 :using_index 创建可延迟的唯一约束。

add_unique_constraint :sections, deferrable: :deferred, name: "unique_position", using_index: "index_sections_on_position"

options 哈希可以包含以下键

:name: 约束名称。默认为 uniq_rails_<identifier>。
:deferrable: 指定唯一约束是否应为可延迟的。有效值为 false 或 :immediate 或 :deferred 用于指定默认行为。默认为 false。
:using_index: 指定现有的唯一索引名称。默认为 nil。
:nulls_not_distinct: 创建唯一约束，其中 NULL 被视为相等。注意：仅受 PostgreSQL 版本 15.0.0 及更高版本支持。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 796
def add_unique_constraint(table_name, column_name = nil, **options)
  options = unique_constraint_options(table_name, column_name, options)
  at = create_alter_table(table_name)
  at.add_unique_constraint(column_name, options)

  execute schema_creation.accept(at)
end

client_min_messages() 链接

返回当前的客户端消息级别。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 291
def client_min_messages
  query_value("SHOW client_min_messages", "SCHEMA")
end

client_min_messages=(level) 链接

设置客户端消息级别。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 296
def client_min_messages=(level)
  internal_execute("SET client_min_messages TO '#{level}'", "SCHEMA")
end

collation() 链接

返回当前的数据库排序规则。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 235
def collation
  query_value("SELECT datcollate FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

create_database(name, options = {}) 链接

创建一个新的 PostgreSQL 数据库。选项包括 :owner、:template、:encoding（默认为 utf8）、:collation、:ctype、:tablespace 和 :connection_limit（注意，MySQL 使用 :charset，而 PostgreSQL 使用 :encoding）。

例子

create_database config[:database], config
create_database 'foo_development', encoding: 'unicode'

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 22
def create_database(name, options = {})
  options = { encoding: "utf8" }.merge!(options.symbolize_keys)

  option_string = options.each_with_object(+"") do |(key, value), memo|
    memo << case key
            when :owner
              " OWNER = \"#{value}\""
            when :template
              " TEMPLATE = \"#{value}\""
            when :encoding
              " ENCODING = '#{value}'"
            when :collation
              " LC_COLLATE = '#{value}'"
            when :ctype
              " LC_CTYPE = '#{value}'"
            when :tablespace
              " TABLESPACE = \"#{value}\""
            when :connection_limit
              " CONNECTION LIMIT = #{value}"
            else
              ""
    end
  end

  execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
end

create_schema(schema_name, force: nil, if_not_exists: nil) 链接

为给定的模式名称创建模式。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 256
def create_schema(schema_name, force: nil, if_not_exists: nil)
  if force && if_not_exists
    raise ArgumentError, "Options `:force` and `:if_not_exists` cannot be used simultaneously."
  end

  if force
    drop_schema(schema_name, if_exists: true)
  end

  execute("CREATE SCHEMA#{' IF NOT EXISTS' if if_not_exists} #{quote_schema_name(schema_name)}")
end

ctype() 链接

返回当前的数据库 ctype。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 240
def ctype
  query_value("SELECT datctype FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

current_database() 链接

返回当前的数据库名称。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 220
def current_database
  query_value("SELECT current_database()", "SCHEMA")
end

current_schema() 链接

返回当前的模式名称。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 225
def current_schema
  query_value("SELECT current_schema", "SCHEMA")
end

drop_schema(schema_name, **options) 链接

删除给定模式名称的模式。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 269
def drop_schema(schema_name, **options)
  execute "DROP SCHEMA#{' IF EXISTS' if options[:if_exists]} #{quote_schema_name(schema_name)} CASCADE"
end

encoding() 链接

返回当前的数据库编码格式。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 230
def encoding
  query_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

exclusion_constraints(table_name) 链接

返回给定表的排他约束数组。排他约束表示为 ExclusionConstraintDefinition 对象。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 663
        def exclusion_constraints(table_name)
          scope = quoted_scope(table_name)

          exclusion_info = internal_exec_query(<<-SQL, "SCHEMA")
            SELECT conname, pg_get_constraintdef(c.oid) AS constraintdef, c.condeferrable, c.condeferred
            FROM pg_constraint c
            JOIN pg_class t ON c.conrelid = t.oid
            JOIN pg_namespace n ON n.oid = c.connamespace
            WHERE c.contype = 'x'
              AND t.relname = #{scope[:name]}
              AND n.nspname = #{scope[:schema]}
          SQL

          exclusion_info.map do |row|
            method_and_elements, predicate = row["constraintdef"].split(" WHERE ")
            method_and_elements_parts = method_and_elements.match(/EXCLUDE(?: USING (?<using>\S+))? \((?<expression>.+)\)/)
            predicate.remove!(/ DEFERRABLE(?: INITIALLY (?:IMMEDIATE|DEFERRED))?/) if predicate
            predicate = predicate.from(2).to(-3) if predicate # strip 2 opening and closing parentheses

            deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"])

            options = {
              name: row["conname"],
              using: method_and_elements_parts["using"].to_sym,
              where: predicate,
              deferrable: deferrable
            }

            ExclusionConstraintDefinition.new(table_name, method_and_elements_parts["expression"], options)
          end
        end

foreign_keys(table_name) 链接

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 584
        def foreign_keys(table_name)
          scope = quoted_scope(table_name)
          fk_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
            SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete, c.convalidated AS valid, c.condeferrable AS deferrable, c.condeferred AS deferred, c.conkey, c.confkey, c.conrelid, c.confrelid
            FROM pg_constraint c
            JOIN pg_class t1 ON c.conrelid = t1.oid
            JOIN pg_class t2 ON c.confrelid = t2.oid
            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
            JOIN pg_namespace t3 ON c.connamespace = t3.oid
            WHERE c.contype = 'f'
              AND t1.relname = #{scope[:name]}
              AND t3.nspname = #{scope[:schema]}
            ORDER BY c.conname
          SQL

          fk_info.map do |row|
            to_table = Utils.unquote_identifier(row["to_table"])
            conkey = row["conkey"].scan(/\d+/).map(&:to_i)
            confkey = row["confkey"].scan(/\d+/).map(&:to_i)

            if conkey.size > 1
              column = column_names_from_column_numbers(row["conrelid"], conkey)
              primary_key = column_names_from_column_numbers(row["confrelid"], confkey)
            else
              column = Utils.unquote_identifier(row["column"])
              primary_key = row["primary_key"]
            end

            options = {
              column: column,
              name: row["name"],
              primary_key: primary_key
            }

            options[:on_delete] = extract_foreign_key_action(row["on_delete"])
            options[:on_update] = extract_foreign_key_action(row["on_update"])
            options[:deferrable] = extract_constraint_deferrable(row["deferrable"], row["deferred"])

            options[:validate] = row["valid"]

            ForeignKeyDefinition.new(table_name, to_table, options)
          end
        end

foreign_table_exists?(table_name) 链接

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 633
def foreign_table_exists?(table_name)
  query_values(data_source_sql(table_name, type: "FOREIGN TABLE"), "SCHEMA").any? if table_name.present?
end

foreign_tables() 链接

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 629
def foreign_tables
  query_values(data_source_sql(type: "FOREIGN TABLE"), "SCHEMA")
end

index_name_exists?(table_name, index_name) 链接

验证具有给定名称的索引是否存在。

来源：显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 68
        def index_name_exists?(table_name, index_name)
          table = quoted_scope(table_name)
          index = quoted_scope(index_name)

          query_value(<<~SQL, "SCHEMA").to_i > 0
            SELECT COUNT(*)
            FROM pg_class t
            INNER JOIN pg_index d ON t.oid = d.indrelid
            INNER JOIN pg_class i ON d.indexrelid = i.oid
            LEFT JOIN pg_namespace n ON n.oid = t.relnamespace
            WHERE i.relkind IN ('i', 'I')
              AND i.relname = #{index[:name]}
              AND t.relname = #{table[:name]}
              AND n.nspname = #{table[:schema]}
          SQL
        end

remove_exclusion_constraint(table_name, expression = nil, **options) 链接

从表中删除给定的排他约束。

remove_exclusion_constraint :products, name: "price_check"

如果存在，expression 参数将被忽略。在迁移的 change 方法中提供它可能会有所帮助，以便它可以被还原。在这种情况下，expression 将由 add_exclusion_constraint 使用。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 768
def remove_exclusion_constraint(table_name, expression = nil, **options)
  excl_name_to_delete = exclusion_constraint_for!(table_name, expression: expression, **options).name

  remove_constraint(table_name, excl_name_to_delete)
end

remove_unique_constraint(table_name, column_name = nil, **options) 链接

从表中删除给定的唯一约束。

remove_unique_constraint :sections, name: "unique_position"

如果存在，column_name 参数将被忽略。在迁移的 change 方法中提供它可能会有所帮助，以便它可以被还原。在这种情况下，column_name 将由 add_unique_constraint 使用。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 823
def remove_unique_constraint(table_name, column_name = nil, **options)
  unique_name_to_delete = unique_constraint_for!(table_name, column: column_name, **options).name

  remove_constraint(table_name, unique_name_to_delete)
end

rename_index(table_name, old_name, new_name) 链接

重命名表的索引。如果新索引名称的长度大于允许的限制，则会引发错误。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 566
def rename_index(table_name, old_name, new_name)
  validate_index_length!(table_name, new_name)

  schema, = extract_schema_qualified_name(table_name)
  execute "ALTER INDEX #{quote_table_name(schema) + '.' if schema}#{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
end

rename_table(table_name, new_name, **options) 链接

重命名表。还会重命名表的 primary key 序列，如果序列名称存在且与 Active Record 默认值匹配。

例子

rename_table('octopuses', 'octopi')

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 434
def rename_table(table_name, new_name, **options)
  validate_table_length!(new_name) unless options[:_uses_legacy_table_name]
  clear_cache!
  schema_cache.clear_data_source_cache!(table_name.to_s)
  schema_cache.clear_data_source_cache!(new_name.to_s)
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
  pk, seq = pk_and_sequence_for(new_name)
  if pk
    # PostgreSQL automatically creates an index for PRIMARY KEY with name consisting of
    # truncated table name and "_pkey" suffix fitting into max_identifier_length number of characters.
    max_pkey_prefix = max_identifier_length - "_pkey".size
    idx = "#{table_name[0, max_pkey_prefix]}_pkey"
    new_idx = "#{new_name[0, max_pkey_prefix]}_pkey"
    execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"

    # PostgreSQL automatically creates a sequence for PRIMARY KEY with name consisting of
    # truncated table name and "#{primary_key}_seq" suffix fitting into max_identifier_length number of characters.
    max_seq_prefix = max_identifier_length - "_#{pk}_seq".size
    if seq && seq.identifier == "#{table_name[0, max_seq_prefix]}_#{pk}_seq"
      new_seq = "#{new_name[0, max_seq_prefix]}_#{pk}_seq"
      execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
    end
  end
  rename_table_indexes(table_name, new_name, **options)
end

schema_exists?(name) 链接

如果模式存在，则返回 true。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 63
def schema_exists?(name)
  query_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = #{quote(name)}", "SCHEMA").to_i > 0
end

schema_names() 链接

返回模式名称数组。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 245
        def schema_names
          query_values(<<~SQL, "SCHEMA")
            SELECT nspname
              FROM pg_namespace
             WHERE nspname !~ '^pg_.*'
               AND nspname NOT IN ('information_schema')
             ORDER by nspname;
          SQL
        end

schema_search_path() 链接

返回活动的模式搜索路径。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 286
def schema_search_path
  @schema_search_path ||= query_value("SHOW search_path", "SCHEMA")
end

schema_search_path=(schema_csv) 链接

将模式搜索路径设置为以逗号分隔的模式名称字符串。以 $ 开头的名称必须用引号括起来（例如 $user => ‘$user’）。参见: www.postgresql.org/docs/current/static/ddl-schemas.html

这不应该被手动调用，而应该在 database.yml 中设置。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 278
def schema_search_path=(schema_csv)
  if schema_csv
    internal_execute("SET search_path TO #{schema_csv}")
    @schema_search_path = schema_csv
  end
end

serial_sequence(table, column) 链接

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 311
def serial_sequence(table, column)
  query_value("SELECT pg_get_serial_sequence(#{quote(table)}, #{quote(column)})", "SCHEMA")
end

unique_constraints(table_name) 链接

返回给定表的唯一约束数组。唯一约束表示为 UniqueConstraintDefinition 对象。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 697
        def unique_constraints(table_name)
          scope = quoted_scope(table_name)

          unique_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
            SELECT c.conname, c.conrelid, c.conkey, c.condeferrable, c.condeferred, pg_get_constraintdef(c.oid) AS constraintdef
            FROM pg_constraint c
            JOIN pg_class t ON c.conrelid = t.oid
            JOIN pg_namespace n ON n.oid = c.connamespace
            WHERE c.contype = 'u'
              AND t.relname = #{scope[:name]}
              AND n.nspname = #{scope[:schema]}
          SQL

          unique_info.map do |row|
            conkey = row["conkey"].delete("{}").split(",").map(&:to_i)
            columns = column_names_from_column_numbers(row["conrelid"], conkey)

            nulls_not_distinct = row["constraintdef"].start_with?("UNIQUE NULLS NOT DISTINCT")
            deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"])

            options = {
              name: row["conname"],
              nulls_not_distinct: nulls_not_distinct,
              deferrable: deferrable
            }

            UniqueConstraintDefinition.new(table_name, columns, options)
          end
        end

validate_check_constraint(table_name, **options) 链接

验证给定的检查约束。

validate_check_constraint :products, name: "price_check"

options 哈希接受与 add_check_constraint[rdoc-ref:ConnectionAdapters::SchemaStatements#add_check_constraint] 相同的键。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 926
def validate_check_constraint(table_name, **options)
  chk_name_to_validate = check_constraint_for!(table_name, **options).name

  validate_constraint table_name, chk_name_to_validate
end

validate_constraint(table_name, constraint_name) 链接

验证给定的约束。

验证 accounts 上名为 constraint_name 的约束。

validate_constraint :accounts, :constraint_name

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 893
def validate_constraint(table_name, constraint_name)
  at = create_alter_table table_name
  at.validate_constraint constraint_name

  execute schema_creation.accept(at)
end

validate_foreign_key(from_table, to_table = nil, **options) 链接

验证给定的外键。

验证 accounts.branch_id 上的外键。

validate_foreign_key :accounts, :branches

验证 accounts.owner_id 上的外键。

validate_foreign_key :accounts, column: :owner_id

验证 accounts 表上名为 special_fk_name 的外键。

validate_foreign_key :accounts, name: :special_fk_name

options 哈希接受与 SchemaStatements#add_foreign_key 相同的键。

来源: 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 915
def validate_foreign_key(from_table, to_table = nil, **options)
  fk_name_to_validate = foreign_key_for!(from_table, to_table: to_table, **options).name

  validate_constraint from_table, fk_name_to_validate
end

模块 ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

实例公有方法

add_exclusion_constraint(table_name, expression, **options) 链接

add_foreign_key(from_table, to_table, **options) 链接

add_unique_constraint(table_name, column_name = nil, **options) 链接

client_min_messages() 链接

client_min_messages=(level) 链接

collation() 链接

create_database(name, options = {}) 链接

create_schema(schema_name, force: nil, if_not_exists: nil) 链接

ctype() 链接

current_database() 链接

current_schema() 链接

drop_schema(schema_name, **options) 链接

encoding() 链接

exclusion_constraints(table_name) 链接

foreign_keys(table_name) 链接

foreign_table_exists?(table_name) 链接

foreign_tables() 链接

index_name_exists?(table_name, index_name) 链接

remove_exclusion_constraint(table_name, expression = nil, **options) 链接

remove_unique_constraint(table_name, column_name = nil, **options) 链接

rename_index(table_name, old_name, new_name) 链接

rename_table(table_name, new_name, **options) 链接

schema_exists?(name) 链接

schema_names() 链接

schema_search_path() 链接

schema_search_path=(schema_csv) 链接

serial_sequence(table, column) 链接

unique_constraints(table_name) 链接

validate_check_constraint(table_name, **options) 链接

validate_constraint(table_name, constraint_name) 链接

validate_foreign_key(from_table, to_table = nil, **options) 链接