277 lines
11 KiB
Python
277 lines
11 KiB
Python
import re
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import cx_Oracle
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from django.db.backends import BaseDatabaseIntrospection, FieldInfo
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from django.utils.encoding import force_text
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foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
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class DatabaseIntrospection(BaseDatabaseIntrospection):
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# Maps type objects to Django Field types.
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data_types_reverse = {
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cx_Oracle.BLOB: 'BinaryField',
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cx_Oracle.CLOB: 'TextField',
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cx_Oracle.DATETIME: 'DateField',
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cx_Oracle.FIXED_CHAR: 'CharField',
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cx_Oracle.NCLOB: 'TextField',
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cx_Oracle.NUMBER: 'DecimalField',
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cx_Oracle.STRING: 'CharField',
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cx_Oracle.TIMESTAMP: 'DateTimeField',
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}
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try:
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data_types_reverse[cx_Oracle.NATIVE_FLOAT] = 'FloatField'
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except AttributeError:
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pass
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try:
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data_types_reverse[cx_Oracle.UNICODE] = 'CharField'
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except AttributeError:
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pass
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def get_field_type(self, data_type, description):
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# If it's a NUMBER with scale == 0, consider it an IntegerField
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if data_type == cx_Oracle.NUMBER and description[5] == 0:
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if description[4] > 11:
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return 'BigIntegerField'
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else:
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return 'IntegerField'
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else:
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return super(DatabaseIntrospection, self).get_field_type(
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data_type, description)
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def get_table_list(self, cursor):
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"Returns a list of table names in the current database."
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cursor.execute("SELECT TABLE_NAME FROM USER_TABLES")
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return [row[0].lower() for row in cursor.fetchall()]
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def get_table_description(self, cursor, table_name):
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"Returns a description of the table, with the DB-API cursor.description interface."
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cursor.execute("SELECT * FROM %s WHERE ROWNUM < 2" % self.connection.ops.quote_name(table_name))
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description = []
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for desc in cursor.description:
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name = force_text(desc[0]) # cx_Oracle always returns a 'str' on both Python 2 and 3
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name = name % {} # cx_Oracle, for some reason, doubles percent signs.
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description.append(FieldInfo(*(name.lower(),) + desc[1:]))
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return description
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def table_name_converter(self, name):
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"Table name comparison is case insensitive under Oracle"
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return name.lower()
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def _name_to_index(self, cursor, table_name):
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"""
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Returns a dictionary of {field_name: field_index} for the given table.
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Indexes are 0-based.
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"""
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return dict((d[0], i) for i, d in enumerate(self.get_table_description(cursor, table_name)))
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def get_relations(self, cursor, table_name):
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"""
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Returns a dictionary of {field_index: (field_index_other_table, other_table)}
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representing all relationships to the given table. Indexes are 0-based.
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"""
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table_name = table_name.upper()
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cursor.execute("""
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SELECT ta.column_id - 1, tb.table_name, tb.column_id - 1
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FROM user_constraints, USER_CONS_COLUMNS ca, USER_CONS_COLUMNS cb,
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user_tab_cols ta, user_tab_cols tb
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WHERE user_constraints.table_name = %s AND
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ta.table_name = user_constraints.table_name AND
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ta.column_name = ca.column_name AND
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ca.table_name = ta.table_name AND
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user_constraints.constraint_name = ca.constraint_name AND
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user_constraints.r_constraint_name = cb.constraint_name AND
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cb.table_name = tb.table_name AND
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cb.column_name = tb.column_name AND
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ca.position = cb.position""", [table_name])
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relations = {}
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for row in cursor.fetchall():
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relations[row[0]] = (row[2], row[1].lower())
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return relations
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def get_key_columns(self, cursor, table_name):
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cursor.execute("""
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SELECT ccol.column_name, rcol.table_name AS referenced_table, rcol.column_name AS referenced_column
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FROM user_constraints c
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JOIN user_cons_columns ccol
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ON ccol.constraint_name = c.constraint_name
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JOIN user_cons_columns rcol
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ON rcol.constraint_name = c.r_constraint_name
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WHERE c.table_name = %s AND c.constraint_type = 'R'""", [table_name.upper()])
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return [tuple(cell.lower() for cell in row)
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for row in cursor.fetchall()]
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def get_indexes(self, cursor, table_name):
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sql = """
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SELECT LOWER(uic1.column_name) AS column_name,
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CASE user_constraints.constraint_type
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WHEN 'P' THEN 1 ELSE 0
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END AS is_primary_key,
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CASE user_indexes.uniqueness
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WHEN 'UNIQUE' THEN 1 ELSE 0
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END AS is_unique
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FROM user_constraints, user_indexes, user_ind_columns uic1
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WHERE user_constraints.constraint_type (+) = 'P'
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AND user_constraints.index_name (+) = uic1.index_name
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AND user_indexes.uniqueness (+) = 'UNIQUE'
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AND user_indexes.index_name (+) = uic1.index_name
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AND uic1.table_name = UPPER(%s)
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AND uic1.column_position = 1
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AND NOT EXISTS (
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SELECT 1
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FROM user_ind_columns uic2
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WHERE uic2.index_name = uic1.index_name
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AND uic2.column_position = 2
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)
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"""
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cursor.execute(sql, [table_name])
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indexes = {}
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for row in cursor.fetchall():
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indexes[row[0]] = {'primary_key': bool(row[1]),
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'unique': bool(row[2])}
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return indexes
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def get_constraints(self, cursor, table_name):
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"""
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Retrieves any constraints or keys (unique, pk, fk, check, index) across one or more columns.
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"""
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constraints = {}
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# Loop over the constraints, getting PKs and uniques
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cursor.execute("""
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SELECT
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user_constraints.constraint_name,
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LOWER(cols.column_name) AS column_name,
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CASE user_constraints.constraint_type
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WHEN 'P' THEN 1
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ELSE 0
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END AS is_primary_key,
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CASE user_indexes.uniqueness
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WHEN 'UNIQUE' THEN 1
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ELSE 0
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END AS is_unique,
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CASE user_constraints.constraint_type
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WHEN 'C' THEN 1
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ELSE 0
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END AS is_check_constraint
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FROM
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user_constraints
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INNER JOIN
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user_indexes ON user_indexes.index_name = user_constraints.index_name
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LEFT OUTER JOIN
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user_cons_columns cols ON user_constraints.constraint_name = cols.constraint_name
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WHERE
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(
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user_constraints.constraint_type = 'P' OR
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user_constraints.constraint_type = 'U'
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)
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AND user_constraints.table_name = UPPER(%s)
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ORDER BY cols.position
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""", [table_name])
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for constraint, column, pk, unique, check in cursor.fetchall():
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# If we're the first column, make the record
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if constraint not in constraints:
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constraints[constraint] = {
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"columns": [],
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"primary_key": pk,
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"unique": unique,
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"foreign_key": None,
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"check": check,
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"index": True, # All P and U come with index, see inner join above
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}
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# Record the details
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constraints[constraint]['columns'].append(column)
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# Check constraints
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cursor.execute("""
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SELECT
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cons.constraint_name,
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LOWER(cols.column_name) AS column_name
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FROM
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user_constraints cons
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LEFT OUTER JOIN
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user_cons_columns cols ON cons.constraint_name = cols.constraint_name
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WHERE
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cons.constraint_type = 'C' AND
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cons.table_name = UPPER(%s)
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ORDER BY cols.position
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""", [table_name])
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for constraint, column in cursor.fetchall():
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# If we're the first column, make the record
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if constraint not in constraints:
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constraints[constraint] = {
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"columns": [],
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"primary_key": False,
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"unique": False,
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"foreign_key": None,
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"check": True,
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"index": False,
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}
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# Record the details
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constraints[constraint]['columns'].append(column)
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# Foreign key constraints
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cursor.execute("""
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SELECT
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cons.constraint_name,
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LOWER(cols.column_name) AS column_name,
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LOWER(rcons.table_name),
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LOWER(rcols.column_name)
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FROM
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user_constraints cons
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INNER JOIN
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user_constraints rcons ON cons.r_constraint_name = rcons.constraint_name
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INNER JOIN
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user_cons_columns rcols ON rcols.constraint_name = rcons.constraint_name
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LEFT OUTER JOIN
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user_cons_columns cols ON cons.constraint_name = cols.constraint_name
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WHERE
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cons.constraint_type = 'R' AND
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cons.table_name = UPPER(%s)
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ORDER BY cols.position
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""", [table_name])
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for constraint, column, other_table, other_column in cursor.fetchall():
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# If we're the first column, make the record
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if constraint not in constraints:
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constraints[constraint] = {
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"columns": [],
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"primary_key": False,
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"unique": False,
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"foreign_key": (other_table, other_column),
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"check": False,
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"index": False,
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}
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# Record the details
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constraints[constraint]['columns'].append(column)
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# Now get indexes
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cursor.execute("""
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SELECT
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index_name,
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LOWER(column_name)
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FROM
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user_ind_columns cols
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WHERE
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table_name = UPPER(%s) AND
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NOT EXISTS (
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SELECT 1
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FROM user_constraints cons
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WHERE cols.index_name = cons.index_name
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)
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ORDER BY cols.column_position
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""", [table_name])
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for constraint, column in cursor.fetchall():
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# If we're the first column, make the record
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if constraint not in constraints:
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constraints[constraint] = {
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"columns": [],
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"primary_key": False,
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"unique": False,
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"foreign_key": None,
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"check": False,
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"index": True,
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}
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# Record the details
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constraints[constraint]['columns'].append(column)
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return constraints
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