Copy database_upgrader Migrator from Etiquette.
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1 changed files with 167 additions and 97 deletions
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@ -6,12 +6,75 @@ import sys
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import bot
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import ycdl
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class Migrator:
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'''
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Many of the upgraders involve adding columns. ALTER TABLE ADD COLUMN only
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allows adding at the end, which I usually don't prefer. In order to add a
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column in the middle, you must rename the table, create a new one, transfer
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the data, and drop the old one. But, foreign keys and indices will still
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point to the old table, which causes broken foreign keys and dropped
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indices. So, the only way to prevent all that is to regenerate all affected
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tables and indices. Rather than parsing relationships to determine the
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affected tables, this implementation just regenerates everything.
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It's kind of horrible but it allows me to have the columns in the order I
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want instead of just always appending. Besides, modifying collations cannot
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be done in-place either.
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If you want to truly remove a table or index and not have it get
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regenerated, just do that before instantiating the Migrator.
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'''
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def __init__(self, ycdldb):
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self.ycdldb = ycdldb
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query = 'SELECT name, sql FROM sqlite_master WHERE type == "table"'
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self.tables = {
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name: {'create': sql, 'transfer': f'INSERT INTO {name} SELECT * FROM {name}_old'}
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for (name, sql) in self.ycdldb.sql_select(query)
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}
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# The user may be adding entirely new tables derived from the data of
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# old ones. We'll need to skip new tables for the rename and drop_old
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# steps. So we track which tables already existed at the beginning.
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self.existing_tables = set(self.tables)
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query = 'SELECT name, sql FROM sqlite_master WHERE type == "index" AND name NOT LIKE "sqlite_%"'
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self.indices = list(self.ycdldb.sql_select(query))
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def go(self):
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# This loop is split in many parts, because otherwise if table A
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# references table B and table A is completely reconstructed, it will
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# be pointing to the version of B which has not been reconstructed yet,
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# which is about to get renamed to B_old and then A's reference will be
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# broken.
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self.ycdldb.sql_execute('PRAGMA foreign_keys = OFF')
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self.ycdldb.sql_execute('BEGIN')
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for (name, table) in self.tables.items():
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if name not in self.existing_tables:
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continue
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self.ycdldb.sql_execute(f'ALTER TABLE {name} RENAME TO {name}_old')
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for (name, table) in self.tables.items():
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self.ycdldb.sql_execute(table['create'])
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for (name, table) in self.tables.items():
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self.ycdldb.sql_execute(table['transfer'])
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for (name, query) in self.tables.items():
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if name not in self.existing_tables:
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continue
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self.ycdldb.sql_execute(f'DROP TABLE {name}_old')
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for (name, query) in self.indices:
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self.ycdldb.sql_execute(query)
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def upgrade_1_to_2(ycdldb):
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'''
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In this version, the `duration` column was added to the videos table.
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'''
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ycdldb.sql.execute('ALTER TABLE videos RENAME TO videos_old')
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ycdldb.sql.execute('''
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m = Migrator(ycdldb)
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m.tables['videos']['create'] = '''
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CREATE TABLE videos(
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id TEXT,
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published INT,
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@ -21,9 +84,9 @@ def upgrade_1_to_2(ycdldb):
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duration INT,
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thumbnail TEXT,
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download TEXT
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)
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''')
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ycdldb.sql.execute('''
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);
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'''
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m.tables['videos']['transfer'] = '''
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INSERT INTO videos SELECT
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id,
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published,
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@ -33,9 +96,10 @@ def upgrade_1_to_2(ycdldb):
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NULL,
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thumbnail,
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download
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FROM videos_old
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''')
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ycdldb.sql.execute('DROP TABLE videos_old')
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FROM videos_old;
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'''
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m.go()
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def upgrade_2_to_3(ycdldb):
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'''
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@ -48,8 +112,9 @@ def upgrade_3_to_4(ycdldb):
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'''
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In this version, the `views` column was added to the videos table.
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'''
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ycdldb.sql.execute('ALTER TABLE videos RENAME TO videos_old')
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ycdldb.sql.execute('''
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m = Migrator(ycdldb)
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m.tables['videos']['create'] = '''
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CREATE TABLE videos(
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id TEXT,
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published INT,
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@ -60,9 +125,9 @@ def upgrade_3_to_4(ycdldb):
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views INT,
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thumbnail TEXT,
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download TEXT
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)
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''')
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ycdldb.sql.execute('''
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);
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'''
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m.tables['videos']['transfer'] = '''
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INSERT INTO videos SELECT
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id,
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published,
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@ -73,34 +138,37 @@ def upgrade_3_to_4(ycdldb):
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NULL,
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thumbnail,
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download
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FROM videos_old
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''')
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ycdldb.sql.execute('DROP TABLE videos_old')
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FROM videos_old;
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'''
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m.go()
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def upgrade_4_to_5(ycdldb):
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'''
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In this version, the `uploads_playlist` column was added to the channels table.
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'''
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ycdldb.sql.execute('ALTER TABLE channels RENAME TO channels_old')
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ycdldb.sql.execute('''
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m = Migrator(ycdldb)
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m.tables['channels']['create'] = '''
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CREATE TABLE channels(
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id TEXT,
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name TEXT,
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uploads_playlist TEXT,
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directory TEXT COLLATE NOCASE,
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automark TEXT
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)
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''')
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ycdldb.sql.execute('''
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);
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'''
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m.tables['channels']['transfer'] = '''
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INSERT INTO channels SELECT
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id,
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name,
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NULL,
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directory,
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automark
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FROM channels_old
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''')
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ycdldb.sql.execute('DROP TABLE channels_old')
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FROM channels_old;
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'''
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m.go()
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rows = ycdldb.sql.execute('SELECT id FROM channels').fetchall()
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channels = [row[0] for row in rows]
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@ -121,8 +189,9 @@ def upgrade_5_to_6(ycdldb):
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to `download_directory` to be in line with the default config's name for
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the same value, and the `queuefile_extension` column was added.
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'''
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ycdldb.sql.execute('ALTER TABLE channels RENAME TO channels_old')
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ycdldb.sql.execute('''
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m = Migrator(ycdldb)
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m.tables['channels']['create'] = '''
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CREATE TABLE channels(
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id TEXT,
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name TEXT,
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@ -130,9 +199,9 @@ def upgrade_5_to_6(ycdldb):
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download_directory TEXT COLLATE NOCASE,
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queuefile_extension TEXT COLLATE NOCASE,
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automark TEXT
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)
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''')
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ycdldb.sql.execute('''
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);
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'''
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m.tables['channels']['transfer'] = '''
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INSERT INTO channels SELECT
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id,
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name,
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@ -140,9 +209,10 @@ def upgrade_5_to_6(ycdldb):
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directory,
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NULL,
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automark
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FROM channels_old
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''')
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ycdldb.sql.execute('DROP TABLE channels_old')
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FROM channels_old;
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'''
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m.go()
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def upgrade_6_to_7(ycdldb):
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'''
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@ -203,7 +273,7 @@ def upgrade_all(data_directory):
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upgrade_function = eval(upgrade_function)
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try:
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ycdldb.sql.execute('BEGIN')
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ycdldb.sql.execute('PRAGMA foreign_keys = ON')
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upgrade_function(ycdldb)
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except Exception as exc:
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ycdldb.rollback()
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