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方法
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实例公共方法

build_explain_clause(options = [])

源代码： 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 96
def build_explain_clause(options = [])
  return "EXPLAIN" if options.empty?

  "EXPLAIN (#{options.join(", ").upcase})"
end

explain(arel, binds = [], options = [])

源代码： 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 7
def explain(arel, binds = [], options = [])
  sql    = build_explain_clause(options) + " " + to_sql(arel, binds)
  result = internal_exec_query(sql, "EXPLAIN", binds)
  PostgreSQL::ExplainPrettyPrinter.new.pp(result)
end

high_precision_current_timestamp()

源代码： 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 92
def high_precision_current_timestamp
  HIGH_PRECISION_CURRENT_TIMESTAMP
end

set_constraints(deferred, *constraints)

设置当前事务中何时检查约束。

不传递任何特定约束名称将为所有可延迟约束设置值。

deferred

有效值为 :deferred 或 :immediate。

请参阅 www.postgresql.org/docs/current/sql-set-constraints.html

源代码： 显示 | 在 GitHub 上

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 110
def set_constraints(deferred, *constraints)
  unless %i[deferred immediate].include?(deferred)
    raise ArgumentError, "deferred must be :deferred or :immediate"
  end

  constraints = if constraints.empty?
    "ALL"
  else
    constraints.map { |c| quote_table_name(c) }.join(", ")
  end
  execute("SET CONSTRAINTS #{constraints} #{deferred.to_s.upcase}")
end