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Code Issues 32 Releases Wiki Activity

boulder-oracle-sprint: DRY refactoring in Oracle backend to reuse sequence reset

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git-svn-id: http://code.djangoproject.com/svn/django/branches/boulder-oracle-sprint@4996 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Boulder Sprinters 2007-04-11 17:30:16 +00:00
parent f44429224a
commit be1357a496
1 changed files with 29 additions and 32 deletions
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61
django/db/backends/oracle/base.py
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@ -183,6 +183,25 @@ def get_autoinc_sql(table):
END;\n""" % (tr_name, quote_name(table), sq_name)
return sequence_sql, trigger_sql
def _get_sequence_reset_sql():
# TODO: colorize this SQL code with style.SQL_KEYWORD(), etc.
return """
DECLARE
startvalue integer;
cval integer;
BEGIN
LOCK TABLE %(table)s IN SHARE MODE;
SELECT NVL(MAX(id), 0) INTO startvalue FROM %(table)s;
SELECT %(sequence)s.nextval INTO cval FROM dual;
cval := startvalue - cval;
IF cval != 0 THEN
EXECUTE IMMEDIATE 'ALTER SEQUENCE %(sequence)s MINVALUE 0 INCREMENT BY '||cval;
SELECT %(sequence)s.nextval INTO cval FROM dual;
EXECUTE IMMEDIATE 'ALTER SEQUENCE %(sequence)s INCREMENT BY 1';
END IF;
COMMIT;
END;\n"""
def get_sql_flush(style, tables, sequences):
"""Return a list of SQL statements required to remove all data from
all tables in the database (without actually removing the tables
@ -198,23 +217,14 @@ def get_sql_flush(style, tables, sequences):
style.SQL_KEYWORD('FROM'),
style.SQL_FIELD(quote_name(table))
) for table in tables]
# You can't ALTER SEQUENCE back to 1 in Oracle. You must DROP and
# CREATE the sequence.
# What? You got something better to do than marching up and
# down the square?
# Since we've just deleted all the rows, running our sequence
# ALTER code will reset the sequence to 0.
for sequence_info in sequences:
table_name = sequence_info['table']
seq_name = get_sequence_name(table_name)
sql.append('%s %s %s;' % \
(style.SQL_KEYWORD('DROP'),
style.SQL_KEYWORD('SEQUENCE'),
style.SQL_FIELD(seq_name))
)
sql.append('%s %s %s;' % \
(style.SQL_KEYWORD('CREATE'),
style.SQL_KEYWORD('SEQUENCE'),
style.SQL_FIELD(seq_name))
)
query = _get_sequence_reset_sql() % {'sequence':seq_name,
'table':quote_name(table_name)}
sql.append(query)
return sql
else:
return []
@ -227,31 +237,18 @@ def get_sql_sequence_reset(style, model_list):
"Returns a list of the SQL statements to reset sequences for the given models."
from django.db import models
output = []
query = """
DECLARE
startvalue integer;
cval integer;
BEGIN
SELECT NVL(MAX(id), 0) INTO startvalue FROM %(table)s;
SELECT %(sequence)s.nextval INTO cval FROM dual;
cval := startvalue - cval;
IF cval != 0 THEN
EXECUTE IMMEDIATE 'ALTER SEQUENCE %(sequence)s MINVALUE 0 INCREMENT BY '||cval;
SELECT %(sequence)s.nextval INTO cval FROM dual;
EXECUTE IMMEDIATE 'ALTER SEQUENCE %(sequence)s INCREMENT BY 1';
END IF;
END; """
query = _get_sequence_reset_sql()
for model in model_list:
for f in model._meta.fields:
if isinstance(f, models.AutoField):
sequence_name = get_sequence_name(model._meta.db_table)
query1 = query % {'sequence':sequence_name, 'table':model._meta.db_table}
output.append(query1)
output.append(query % {'sequence':sequence_name,
'table':model._meta.db_table})
break # Only one AutoField is allowed per model, so don't bother continuing.
for f in model._meta.many_to_many:
sequence_name = get_sequence_name(f.m2m_db_table())
query2 = query % {'sequence':sequence_name, 'table':f.m2m_db_table()}
output.append(query2)
output.append(query % {'sequence':sequence_name,
'table':f.m2m_db_table()})
return output
def get_trigger_name(table):