Class: DBLeftovers::PostgresDatabaseInterface

Inherits:
GenericDatabaseInterface show all
Defined in:
lib/db_leftovers/postgres_database_interface.rb

Instance Method Summary collapse

Methods inherited from GenericDatabaseInterface

#execute_add_constraint, #execute_add_foreign_key, #execute_add_index, #execute_drop_constraint, #execute_drop_foreign_key, #execute_drop_index, #execute_sql

Constructor Details

#initialize(conn = nil) ⇒ PostgresDatabaseInterface

Returns a new instance of PostgresDatabaseInterface.



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# File 'lib/db_leftovers/postgres_database_interface.rb', line 5

def initialize(conn=nil)
  @conn = conn || ActiveRecord::Base.connection
end

Instance Method Details

#lookup_all_constraints ⇒ Object 



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# File 'lib/db_leftovers/postgres_database_interface.rb', line 109

def lookup_all_constraints
  ret = {}
  sql = <<-EOQ
      SELECT  c.conname,
              t.relname,
              pg_get_expr(c.conbin, c.conrelid)
      FROM    pg_catalog.pg_constraint c,
              pg_catalog.pg_class t,
              pg_catalog.pg_namespace n
      WHERE   c.contype = 'c'
      AND     c.conrelid = t.oid
      AND     t.relkind = 'r'
      AND     n.oid = t.relnamespace
      AND     n.nspname NOT IN ('pg_catalog', 'pg_toast')
      AND     pg_catalog.pg_table_is_visible(t.oid)
  EOQ
  @conn.select_rows(sql).each do |constr_name, on_table, check_expr|
    ret[constr_name] = Constraint.new(constr_name, on_table, remove_outer_parens(check_expr))
  end
  return ret
end

#lookup_all_foreign_keys ⇒ Object 



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# File 'lib/db_leftovers/postgres_database_interface.rb', line 63

def lookup_all_foreign_keys
  # confdeltype: a=nil, c=cascade, n=null
  ret = {}
  # TODO: Support multi-column foreign keys:
  sql = <<-EOQ
      SELECT  c.conname,
              t1.relname AS from_table,
              a1.attname AS from_column,
              t2.relname AS to_table,
              a2.attname AS to_column,
              c.confdeltype
      FROM    pg_catalog.pg_constraint c,
              pg_catalog.pg_class t1,
              pg_catalog.pg_class t2,
              pg_catalog.pg_attribute a1,
              pg_catalog.pg_attribute a2,
              pg_catalog.pg_namespace n1,
              pg_catalog.pg_namespace n2
      WHERE   c.conrelid = t1.oid
      AND     c.confrelid = t2.oid
      AND     c.contype = 'f'
      AND     a1.attrelid = t1.oid
      AND     a1.attnum = ANY(c.conkey)
      AND     a2.attrelid = t2.oid
      AND     a2.attnum = ANY(c.confkey)
      AND     t1.relkind = 'r'
      AND     t2.relkind = 'r'
      AND     n1.oid = t1.relnamespace
      AND     n2.oid = t2.relnamespace
      AND     n1.nspname NOT IN ('pg_catalog', 'pg_toast')
      AND     n2.nspname NOT IN ('pg_catalog', 'pg_toast')
      AND     pg_catalog.pg_table_is_visible(t1.oid)
      AND     pg_catalog.pg_table_is_visible(t2.oid)
  EOQ
  @conn.select_rows(sql).each do |constr_name, from_table, from_column, to_table, to_column, del_type|
    del_type = case del_type
               when 'a'; nil
               when 'c'; :cascade
               when 'n'; :set_null
               else; raise "Unknown del type: #{del_type}"
               end
    ret[constr_name] = ForeignKey.new(from_table, from_column, to_table, to_column, :name => constr_name, :on_delete => del_type)
  end
  return ret
end

#lookup_all_indexes ⇒ Object 



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# File 'lib/db_leftovers/postgres_database_interface.rb', line 9

def lookup_all_indexes
  ret = {}
  sql = <<-EOQ
      SELECT  ix.indexrelid,
              ix.indrelid,
              t.relname AS table_name,
              i.relname AS index_name,
              ix.indisunique AS is_unique,
              array_to_string(ix.indkey, ',') AS column_numbers,
              am.amname AS index_type,
              pg_get_expr(ix.indpred, ix.indrelid) AS where_clause,
              pg_get_expr(ix.indexprs, ix.indrelid) AS index_function
      FROM    pg_class t,
              pg_class i,
              pg_index ix,
              pg_namespace n,
              pg_am am
      WHERE   t.oid = ix.indrelid
      AND     n.oid = t.relnamespace
      AND     i.oid = ix.indexrelid
      AND     t.relkind = 'r'
      AND     n.nspname NOT IN ('pg_catalog', 'pg_toast')
      AND     pg_catalog.pg_table_is_visible(t.oid)
      AND     NOT ix.indisprimary
      AND     i.relam = am.oid
      GROUP BY  t.relname,
                i.relname,
                ix.indisunique,
                ix.indexrelid,
                ix.indrelid,
                ix.indkey,
                am.amname,
                ix.indpred,
                ix.indexprs
      ORDER BY t.relname, i.relname
  EOQ
  @conn.select_rows(sql).each do |indexrelid, indrelid, table_name, index_name, is_unique, column_numbers, index_method, where_clause, index_function|
    where_clause = remove_outer_parens(where_clause) if where_clause
    index_method = nil if index_method == 'btree'
    ret[index_name] = Index.new(
      table_name,
      column_names_for_index(indrelid, column_numbers.split(",")),
      unique: is_unique == 't',
      where: where_clause,
      function: index_function,
      using: index_method,
      name: index_name
    )
  end
  return ret
end