class PgDiffIndexes(object):

@staticmethod

def createIndexes(writer, oldSchema, newSchema, searchPathHelper):

for newTableName, newTable in newSchema.tables.items():

# Add new indexes

if oldSchema is None:

for index in newTable.indexes.values():

searchPathHelper.outputSearchPath()

writer.writeln(index.getCreationSQL())

else:

for index in PgDiffIndexes.getNewIndexes(oldSchema.getTable(newTableName), newTable):

searchPathHelper.outputSearchPath(writer)

writer.writeln(index.getCreationSQL())

@staticmethod

def dropIndexes(writer, oldSchema, newSchema, searchPathHelper):

for newTableName in newSchema.tables:

oldTable = None

if oldSchema is not None:

oldTable = oldSchema.tables.get(newTableName)

newTable = newSchema.tables[newTableName]

# Drop indexes that do not exist in new schema or are modified

for index in PgDiffIndexes.getDropIndexes(oldTable, newTable):

searchPathHelper.outputSearchPath(writer)

writer.writeln(index.getDropSQL())

@staticmethod

def alterComments(writer, oldSchema, newSchema, searchPathHelper):

if oldSchema is None:

return

for oldIndexName in oldSchema.indexes:

newIndex = newSchema.indexes.get(oldIndexName)

if newIndex is None:

continue

oldIndex = newSchema.indexes[oldIndexName]

# sbSQL = []

if (oldIndex.comment is None

and newIndex.comment is not None

or oldIndex.comment is not None

and newIndex.comment is not None

and oldIndex.comment != newIndex.comment):

searchPathHelper.outputSearchPath(writer)

writer.write("COMMENT ON INDEX ")

writer.write(PgDiffUtils.getQuotedName(newIndex.name))

writer.write(" IS ")

writer.write(newIndex.comment)

writer.writeln(';')

elif oldIndex.comment is not None and newIndex.comment is None:

searchPathHelper.outputSearchPath(writer)

writer.write("COMMENT ON INDEX ");

writer.write(PgDiffUtils.getQuotedName(newIndex.name))

writer.writeln(" IS NULL;")

@staticmethod

def getNewIndexes(oldTable, newTable):

result = []

if newTable is not None:

if oldTable is None:

for index in newTable.indexes.values():

result.append(index)

else:

for indexName, index in newTable.indexes.items():

if (indexName not in oldTable.indexes

or oldTable.indexes[indexName] != index):

result.append(index)

return result

@staticmethod

def getDropIndexes(oldTable, newTable):

result = list()

if (newTable is not None and oldTable is not None):

for indexName in oldTable.indexes:

if (indexName not in newTable.indexes

or oldTable.indexes[indexName] != newTable.indexes[indexName]):

result.append(oldTable.indexes[indexName])

return result