Module: PgPower::Tools
Overview
Provides utility methods to work with PostgreSQL databases. Usage:
PgPower::Tools.create_schema "services" # => create new PG schema "services"
PgPower::Tools.create_schema "nets"
PgPower::Tools.drop_schema "services" # => remove the schema
PgPower::Tools.schemas # => ["public", "information_schema", "nets"]
PgPower::Tools.move_table_to_schema :computers, :nets
PgPower::Tools.create_view view_name, view_definition # => creates new DB view
PgPower::Tools.drop_view view_name # => removes the view
PgPower::Tools.views # => ["x_view", "y_view", "z_view"]
Instance Method Summary collapse
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#create_schema(schema_name) ⇒ Object
Creates PostgreSQL schema.
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#create_view(view_name, view_definition) ⇒ Object
Creates PostgreSQL view.
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#drop_schema(schema_name) ⇒ Object
Drops PostgreSQL schema.
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#drop_view(view_name) ⇒ Object
Drops PostgreSQL view.
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#move_table_to_schema(table, new_schema) ⇒ Object
Move table to another schema without loosing data, indexes or constraints.
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#schemas ⇒ Object
Returns an array of existing schemas.
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#to_schema_and_table(table_name) ⇒ Array[String, String]
Extract schema name and table name from qualified table name.
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#views ⇒ Object
Returns an array of existing, non system views.
Instance Method Details
#create_schema(schema_name) ⇒ Object
Creates PostgreSQL schema
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# File 'lib/pg_power/tools.rb', line 16 def create_schema(schema_name) sql = %{CREATE SCHEMA "#{schema_name}"} connection.execute sql end |
#create_view(view_name, view_definition) ⇒ Object
Creates PostgreSQL view
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# File 'lib/pg_power/tools.rb', line 45 def create_view(view_name, view_definition) sql = "CREATE VIEW #{view_name} AS #{view_definition}" connection.execute sql end |
#drop_schema(schema_name) ⇒ Object
Drops PostgreSQL schema
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# File 'lib/pg_power/tools.rb', line 22 def drop_schema(schema_name) sql = %{DROP SCHEMA "#{schema_name}"} connection.execute sql end |
#drop_view(view_name) ⇒ Object
Drops PostgreSQL view
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# File 'lib/pg_power/tools.rb', line 52 def drop_view(view_name) sql = "DROP VIEW #{view_name}" connection.execute sql end |
#move_table_to_schema(table, new_schema) ⇒ Object
Move table to another schema without loosing data, indexes or constraints.
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# File 'lib/pg_power/tools.rb', line 36 def move_table_to_schema(table, new_schema) schema, table = to_schema_and_table(table) sql = %{ALTER TABLE "#{schema}"."#{table}" SET SCHEMA "#{new_schema}"} connection.execute sql end |
#schemas ⇒ Object
Returns an array of existing schemas.
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# File 'lib/pg_power/tools.rb', line 28 def schemas sql = "SELECT nspname FROM pg_namespace WHERE nspname !~ '^pg_.*' order by nspname" connection.query(sql).flatten end |
#to_schema_and_table(table_name) ⇒ Array[String, String]
Extract schema name and table name from qualified table name
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# File 'lib/pg_power/tools.rb', line 76 def to_schema_and_table(table_name) table, schema = table_name.to_s.split(".", 2).reverse schema ||= "public" [schema, table] end |
#views ⇒ Object
Returns an array of existing, non system views.
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# File 'lib/pg_power/tools.rb', line 58 def views sql = <<-SQL SELECT table_schema, table_name, view_definition FROM INFORMATION_SCHEMA.views WHERE table_schema NOT IN ('pg_catalog','information_schema') SQL connection.execute sql end |