Constraint factory

Factory producing a class for defining a table-level constraint on the database table, permit to support a composite primary key. Contains the Field class for defining column-level constraints.

xlsx2sqlite.constraint_factory module

class xlsx2sqlite.constraint_factory.Field(field_name=None, field_type=None, definition=None)

Bases: object

Represents a database field.

Parameters

• type_of (str) –

  The type to assign to the database table column, choose between:

  • Field: generic field without a column level constraint

  • Unique: field with a UNIQUE clause

  • PrimaryKey: field with PRIMARY KEY column level constraint

  • NotNullField: set a NOT NULL column constraint on the database column

• field_name (str) – Label for the column of the database table.

• field_type (str) – Column type as a string defined in sqlite column types.

• definition (str) – Type of column-level constraint to declare.

Returns

An instance of a Field object with a to_sql() method that returns an appropriate SQL string.

Return type

object

DEFINITIONS = {'Field': None, 'Unique': 'UNIQUE', 'PrimaryKey': 'NOT NULL PRIMARY KEY', 'NotNull': 'NOT NULL', None: None}

SPACE_DELIM = ' '

This dictionary represents the column-level constraints as SQL strings.

label()

A form of the string with the leading and trailing characters removed.

Returns

A form of the string with the leading and trailing characters removed.

Return type

str

to_sql()

Return a suitable string for using in the database.

Returns

A capitalized form of the string with the leading and trailing characters removed.

Return type

str

xlsx2sqlite.constraint_factory.create_table_constraint(clause: str, columns: list) → object

Table-level constraint class factory, valid clauses are:

• “Unique”

• “PrimaryKey”

Returns

An instance of TableConstraint, a class that represents a SQL table level constraint

Return type

object