Class: XMigra::DeclarativeSupport::Table
- Defined in:
- lib/xmigra/declarative_support/table.rb
Defined Under Namespace
Classes: CheckConstraint, Column, ColumnCreationFragment, ColumnListConstraint, Constraint, DefaultConstraint, Delta, ForeignKey, PrimaryKey, UniquenessConstraint
Instance Attribute Summary collapse
-
#constraints ⇒ Object
readonly
Returns the value of attribute constraints.
-
#extensions ⇒ Object
readonly
Returns the value of attribute extensions.
-
#name ⇒ Object
Returns the value of attribute name.
Class Method Summary collapse
Instance Method Summary collapse
- #add_default(colname, expression, constr_name = nil) ⇒ Object
- #add_table_columns_sql_statements(column_name_type_pairs) ⇒ Object
- #add_table_constraints_sql_statements(constraint_def_clauses) ⇒ Object
- #alter_table_columns_sql_statements(column_name_type_pairs) ⇒ Object
- #column_alteration_occurs?(a, b) ⇒ Boolean
- #column_creation_sql_fragment(column) ⇒ Object
- #columns ⇒ Object
- #creation_sql ⇒ Object
- #destruction_sql ⇒ Object
- #get_column(name) ⇒ Object
- #has_column?(name) ⇒ Boolean
-
#initialize(name, structure) ⇒ Table
constructor
A new instance of Table.
- #remove_table_columns_sql_statements(column_names) ⇒ Object
- #remove_table_constraints_sql_statements(constraint_names) ⇒ Object
- #sql_to_effect_from(old_state) ⇒ Object
- #table_creation_items ⇒ Object
Methods included from ImpdeclMigrationAdder::SupportedDatabaseObject
Constructor Details
#initialize(name, structure) ⇒ Table
Returns a new instance of Table.
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# File 'lib/xmigra/declarative_support/table.rb', line 314 def initialize(name, structure) structure = StructureReader.new(structure) @name = name constraints = {} @columns_by_name = (structure.array_fetch('columns', ->(c) {c['name']}) || raise( SpecificationError, "No columns specified for table #{@name}" )).inject({}) do |result, item| column = Column.new(item) result[column.name] = column if !(col_default = column.default_constraint).nil? constraints[col_default.name] = col_default end result end @primary_key = columns.select(&:primary_key?).tap do |cols| break nil if cols.empty? pk = PrimaryKey.new( "PK_#{name.gsub('.', '_')}", StructureReader.new({'columns'=>cols.map(&:name)}) ) break (constraints[pk.name] = pk) end @constraints = (structure['constraints'] || []).inject(constraints) do |result, name_spec_pair| constraint = Constraint.deserialize(*name_spec_pair) if result.has_key?(constraint.name) raise SpecificationError, "Constraint #{constraint.name} is specified multiple times" end result[constraint.name] = constraint # Link DefaultConstraints to their respective Columns # because the constraint object is needed for column creation if constraint.kind_of? DefaultConstraint unless (col = get_column(constraint.column)).default_constraint.nil? raise SpecificationError, "Default constraint #{constraint.name} attempts to constrain #{constraint.column} which already has a default constraint" end col.default_constraint = constraint end result end errors = [] @constraints.each_value do |constraint| if constraint.kind_of? PrimaryKey unless @primary_key.nil? || constraint.equal?(@primary_key) raise SpecificationError, "Multiple primary keys specified" end @primary_key = constraint end if constraint.kind_of? ColumnListConstraint unknown_cols = constraint.constrained_colnames.reject do |colname| has_column?(colname) end unless unknown_cols.empty? errors << "#{constraint.class::IDENTIFIER} constraint #{constraint.name} references unknown column(s): #{unknown_cols.join(', ')}" end end end structure.each_unused_standard_key do |k| errors << "Unrecognized standard key #{k.join('.')}" end unless errors.empty? raise SpecificationError, errors.join("\n") end @extensions = structure.each_extension.inject({}) do |result, kv_pair| key, value = kv_pair result[key] = value result end end |
Instance Attribute Details
#constraints ⇒ Object (readonly)
Returns the value of attribute constraints.
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# File 'lib/xmigra/declarative_support/table.rb', line 393 def constraints @constraints end |
#extensions ⇒ Object (readonly)
Returns the value of attribute extensions.
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# File 'lib/xmigra/declarative_support/table.rb', line 393 def extensions @extensions end |
#name ⇒ Object
Returns the value of attribute name.
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# File 'lib/xmigra/declarative_support/table.rb', line 392 def name @name end |
Class Method Details
.decldoc ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 9 def self.decldoc <<END_OF_HELP The "!table" tag declares a table within the database using two standard top- level keys: a required "columns" key and an optional "constraints" key. The value of the "columns" key is a sequence of mappings, each giving "name" and "type". The value of the "type" key should be a type according to the database system in use. The "nullable" key (with a default value of true) can map to false to indicate that the column should not accept null values. The key "primary key", whose value is interpreted as a Boolean, can be used to indicate a primary key without using the more explicit "constraints" syntax. Including a "default" key indicates a default constraint on the column, where the value of the key is an expression to use for computing the default value (which may be constrained by the database system in use). The value of the "constraints" key is a mapping from constraint name to constraint definition (itself a mapping). The constraint type can either be explicit through use of the "type" key in the constraint definition or implicit through a prefix used to start the constraint name (and no explicit constraint type). The available constraint types are: Explicit type Implicit prefix ------------- --------------- primary key PK_ unique UQ_ foreign key FK_ check CK_ default DF_ Primary key and unique constraint definitions must have a "columns" key that is a sequence of column names. Only one primary key constraint may be specified, whether through use of "primary key" keys in column mappings or explicitly in the "constraints" section. For foreign key constraint definitions, the value of the "columns" key must be a mapping of referring column name to referenced column name. Check constraint definitions must have a "verify" key whose value is an SQL expression to be checked for all records. Default constraints (when given explicitly) must have a "value" key giving the expression (with possible limitations imposed by the database system in use) for the default value and an indication of the constrained column: either a "column" key giving explicit reference to a column or, if the constraint name starts with the implicit prefix, the part of the constraint name after the prefix. When specifying SQL expressions in YAML, make sure to use appropriate quoting. For example, where apostrophes delimit string literals in SQL and it might be tempting to write a default expression with only one set of apostrophes around it, YAML also uses apostrophes (or "single quotes") to mark a scalar value (a string unless otherwise tagged), and so the apostrophes are consumed when the YAML is parsed. Either use a triple-apostrophe (YAML consumes the first, converts the pair of second and third into a single apostrophe, and does the reverse sequence at the end of the scalar) or use a block scalar (literal or folded), preferably chopped (i.e. "|-" or ">-"). The rule is: whatever YAML parsing sees as the value of the scalar, that is the SQL expression to be used. Extended information may be added to any standard-structure mapping in the declarative document by using any string key beginning with "X-" (the LATIN CAPITAL LETTER X followed by a HYPHEN-MINUS). All other keys are reserved for future expansion and may cause an error when generating implementing SQL. END_OF_HELP #' end |
Instance Method Details
#add_default(colname, expression, constr_name = nil) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 407 def add_default(colname, expression, constr_name=nil) col = get_column(colname) unless col.default_constraint.nil? raise "#{colname} already has a default constraint" end constr_name ||= "DF_#{colname}" if constraints[constr_name] raise "Constraint #{constr_name} already exists" end constraints[constr_name] = col.default_constraint = DefaultConstraint.new( constr_name, StructureReader.new({ 'column'=>colname, 'value'=>expression, }) ) end |
#add_table_columns_sql_statements(column_name_type_pairs) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 563 def add_table_columns_sql_statements(column_name_type_pairs) column_name_type_pairs.map do |col_name, col_type| "ALTER TABLE #{name} ADD COLUMN #{col_name} #{col_type};" end end |
#add_table_constraints_sql_statements(constraint_def_clauses) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 579 def add_table_constraints_sql_statements(constraint_def_clauses) constraint_def_clauses.map do |create_clause| "ALTER TABLE #{name} ADD #{create_clause};" end end |
#alter_table_columns_sql_statements(column_name_type_pairs) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 569 def alter_table_columns_sql_statements(column_name_type_pairs) raise(NotImplementedError, "SQL 92 does not provide a standard way to alter a column's type") unless column_name_type_pairs.empty? end |
#column_alteration_occurs?(a, b) ⇒ Boolean
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# File 'lib/xmigra/declarative_support/table.rb', line 553 def column_alteration_occurs?(a, b) [[a, b], [b, a]].map {|pair| alter_table_columns_sql_statements([pair])}.inject(&:!=) end |
#column_creation_sql_fragment(column) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 544 def column_creation_sql_fragment(column) "#{column.name} #{column.type}".tap do |result| if dc = column.default_constraint result << " CONSTRAINT #{dc.name} DEFAULT #{dc.expression}" end result << " NOT NULL" unless column.nullable? end end |
#columns ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 395 def columns @columns_by_name.values end |
#creation_sql ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 425 def creation_sql "CREATE TABLE #{name} (\n" + \ table_creation_items.map {|item| " #{item.creation_sql}"}.join(",\n") + "\n" + \ ");" end |
#destruction_sql ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 585 def destruction_sql "DROP TABLE #{name};" end |
#get_column(name) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 399 def get_column(name) @columns_by_name[name] end |
#has_column?(name) ⇒ Boolean
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# File 'lib/xmigra/declarative_support/table.rb', line 403 def has_column?(name) @columns_by_name.has_key? name end |
#remove_table_columns_sql_statements(column_names) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 573 def remove_table_columns_sql_statements(column_names) column_names.map do |col_name| "ALTER TABLE #{name} DROP COLUMN #{col_name};" end end |
#remove_table_constraints_sql_statements(constraint_names) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 557 def remove_table_constraints_sql_statements(constraint_names) constraint_names.map do |constr| "ALTER TABLE #{name} DROP CONSTRAINT #{constr};" end end |
#sql_to_effect_from(old_state) ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 441 def sql_to_effect_from(old_state) delta = Delta.new(old_state, self) parts = [] # Remove constraints parts.concat remove_table_constraints_sql_statements( delta.constraints_to_drop ) # Add new columns parts.concat add_table_columns_sql_statements( delta.new_columns.lazy.map {|col| [col.name, col.type]} ).to_a # Alter existing columns parts.concat alter_table_columns_sql_statements( delta.altered_column_pairs ).to_a # Remove columns parts.concat remove_table_columns_sql_statements( delta.removed_columns.lazy.map(&:name) ).to_a # Add constraints parts.concat add_table_constraints_sql_statements( delta.new_constraint_sql_clauses ).to_a (extensions.keys + old_state.extensions.keys).uniq.sort.each do |ext_key| case when extensions.has_key?(ext_key) && !old_state.extensions.has_key?(ext_key) parts << "-- TODO: New extension #{ext_key}" when old_state.extensions.has_key?(ext_key) && !extensions.has_key?(ext_key) parts << "-- TODO: Extension #{ext_key} removed" else parts << "-- TODO: Modification to extension #{ext_key}" end end return parts.join("\n") end |
#table_creation_items ⇒ Object
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# File 'lib/xmigra/declarative_support/table.rb', line 431 def table_creation_items table_items = [] table_items.concat(columns .map {|col| ColumnCreationFragment.new(self, col)} ) table_items.concat(constraints.values .reject(&:only_on_column_at_creation?) ) end |