Support for query placeholders in `db.select`
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D90FBA7F76362774
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@ -3,9 +3,11 @@
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"""
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import time
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from typing import Optional
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from sqlalchemy import create_engine, Table, MetaData
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from sqlalchemy.engine import Engine
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from sqlalchemy.sql import text
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from platypush.plugins import Plugin, action
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@ -23,10 +25,17 @@ class DbPlugin(Plugin):
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def __init__(self, engine=None, *args, **kwargs):
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"""
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:param engine: Default SQLAlchemy connection engine string (e.g. ``sqlite:///:memory:`` or ``mysql://user:pass@localhost/test``) that will be used. You can override the default engine in the db actions.
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:param engine: Default SQLAlchemy connection engine string (e.g.
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``sqlite:///:memory:`` or ``mysql://user:pass@localhost/test``)
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that will be used. You can override the default engine in the db
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actions.
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:type engine: str
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:param args: Extra arguments that will be passed to ``sqlalchemy.create_engine`` (see https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to ``sqlalchemy.create_engine`` (seehttps:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:param args: Extra arguments that will be passed to
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``sqlalchemy.create_engine`` (see
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https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to
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``sqlalchemy.create_engine``
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(see https:///docs.sqlalchemy.org/en/latest/core/engines.html)
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"""
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super().__init__()
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@ -41,11 +50,11 @@ class DbPlugin(Plugin):
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return create_engine(engine, *args, **kwargs)
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assert self.engine
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return self.engine
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# noinspection PyUnusedLocal
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@staticmethod
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def _build_condition(table, column, value):
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def _build_condition(table, column, value): # type: ignore
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if isinstance(value, str):
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value = "'{}'".format(value)
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elif not isinstance(value, int) and not isinstance(value, float):
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@ -69,8 +78,12 @@ class DbPlugin(Plugin):
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:type statement: str
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:param engine: Engine to be used (default: default class engine)
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:type engine: str
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:param args: Extra arguments that will be passed to ``sqlalchemy.create_engine`` (see https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to ``sqlalchemy.create_engine`` (seehttps:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:param args: Extra arguments that will be passed to
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``sqlalchemy.create_engine`` (see
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https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to
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``sqlalchemy.create_engine``
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(see https:///docs.sqlalchemy.org/en/latest/core/engines.html)
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"""
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engine = self._get_engine(engine, *args, **kwargs)
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@ -106,24 +119,42 @@ class DbPlugin(Plugin):
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return table, engine
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@action
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def select(self, query=None, table=None, filter=None, engine=None, *args, **kwargs):
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def select(
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self,
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query=None,
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table=None,
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filter=None,
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engine=None,
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data: Optional[dict] = None,
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*args,
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**kwargs
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):
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"""
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Returns rows (as a list of hashes) given a query.
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:param query: SQL to be executed
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:type query: str
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:param filter: Query WHERE filter expressed as a dictionary. This approach is preferred over specifying raw SQL
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in ``query`` as the latter approach may be prone to SQL injection, unless you need to build some complex
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SQL logic.
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:param filter: Query WHERE filter expressed as a dictionary. This
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approach is preferred over specifying raw SQL
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in ``query`` as the latter approach may be prone to SQL injection,
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unless you need to build some complex SQL logic.
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:type filter: dict
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:param table: If you specified a filter instead of a raw query, you'll have to specify the target table
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:param table: If you specified a filter instead of a raw query, you'll
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have to specify the target table
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:type table: str
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:param engine: Engine to be used (default: default class engine)
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:type engine: str
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:param args: Extra arguments that will be passed to ``sqlalchemy.create_engine``
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(see https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to ``sqlalchemy.create_engine``
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(seehttps:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:param data: If ``query`` is an SQL string, then you can use
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SQLAlchemy's *placeholders* mechanism. You can specify placeholders
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in the query for values that you want to be safely serialized, and
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their values can be specified on the ``data`` attribute in a
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``name`` ➡️ ``value`` mapping format.
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:param args: Extra arguments that will be passed to
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``sqlalchemy.create_engine`` (see
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https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to
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``sqlalchemy.create_engine`` (see
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https:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:returns: List of hashes representing the result rows.
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Examples:
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@ -136,7 +167,10 @@ class DbPlugin(Plugin):
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"action": "db.select",
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"args": {
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"engine": "sqlite:///:memory:",
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"query": "SELECT id, name FROM table"
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"query": "SELECT id, name FROM table WHERE name = :name",
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"data": {
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"name": "foobar"
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}
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}
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}
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@ -165,19 +199,24 @@ class DbPlugin(Plugin):
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engine = self._get_engine(engine, *args, **kwargs)
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if isinstance(query, str):
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query = text(query)
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if table:
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table, engine = self._get_table(table, engine=engine, *args, **kwargs)
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query = table.select()
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if filter:
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for (k,v) in filter.items():
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for (k, v) in filter.items():
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query = query.where(self._build_condition(table, k, v))
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if query is None:
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raise RuntimeError('You need to specify either "query", or "table" and "filter"')
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raise RuntimeError(
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'You need to specify either "query", or "table" and "filter"'
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)
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with engine.connect() as connection:
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result = connection.execute(query)
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result = connection.execute(query, **(data or {}))
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columns = result.keys()
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rows = [
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{col: row[i] for i, col in enumerate(list(columns))}
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@ -187,8 +226,16 @@ class DbPlugin(Plugin):
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return rows
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@action
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def insert(self, table, records, engine=None, key_columns=None,
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on_duplicate_update=False, *args, **kwargs):
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def insert(
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self,
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table,
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records,
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engine=None,
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key_columns=None,
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on_duplicate_update=False,
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*args,
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**kwargs
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):
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"""
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Inserts records (as a list of hashes) into a table.
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@ -198,12 +245,20 @@ class DbPlugin(Plugin):
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:type records: list
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:param engine: Engine to be used (default: default class engine)
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:type engine: str
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:param key_columns: Set it to specify the names of the key columns for ``table``. Set it if you want your statement to be executed with the ``on_duplicate_update`` flag.
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:param key_columns: Set it to specify the names of the key columns for
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``table``. Set it if you want your statement to be executed with
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the ``on_duplicate_update`` flag.
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:type key_columns: list
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:param on_duplicate_update: If set, update the records in case of duplicate rows (default: False). If set, you'll need to specify ``key_columns`` as well.
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:param on_duplicate_update: If set, update the records in case of
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duplicate rows (default: False). If set, you'll need to specify
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``key_columns`` as well.
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:type on_duplicate_update: bool
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:param args: Extra arguments that will be passed to ``sqlalchemy.create_engine`` (see https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to ``sqlalchemy.create_engine`` (seehttps:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:param args: Extra arguments that will be passed to
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``sqlalchemy.create_engine`` (see
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https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to
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``sqlalchemy.create_engine``
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(see https:///docs.sqlalchemy.org/en/latest/core/engines.html)
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Example:
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@ -238,15 +293,21 @@ class DbPlugin(Plugin):
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for record in records:
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table, engine = self._get_table(table, engine=engine, *args, **kwargs)
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insert = table.insert().values(**record)
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try:
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engine.execute(insert)
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except Exception as e:
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if on_duplicate_update and key_columns:
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self.update(table=table, records=records,
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key_columns=key_columns, engine=engine,
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*args, **kwargs)
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self.update(
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table=table,
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records=records,
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key_columns=key_columns,
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engine=engine,
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*args,
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**kwargs
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)
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else:
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raise e
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@ -263,8 +324,12 @@ class DbPlugin(Plugin):
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:type key_columns: list
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:param engine: Engine to be used (default: default class engine)
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:type engine: str
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:param args: Extra arguments that will be passed to ``sqlalchemy.create_engine`` (see https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to ``sqlalchemy.create_engine`` (seehttps:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:param args: Extra arguments that will be passed to
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``sqlalchemy.create_engine`` (see
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https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to
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``sqlalchemy.create_engine``
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(see https:///docs.sqlalchemy.org/en/latest/core/engines.html)
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Example:
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@ -297,12 +362,12 @@ class DbPlugin(Plugin):
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for record in records:
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table, engine = self._get_table(table, engine=engine, *args, **kwargs)
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key = { k:v for (k,v) in record.items() if k in key_columns }
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values = { k:v for (k,v) in record.items() if k not in key_columns }
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key = {k: v for (k, v) in record.items() if k in key_columns}
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values = {k: v for (k, v) in record.items() if k not in key_columns}
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update = table.update()
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for (k,v) in key.items():
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for (k, v) in key.items():
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update = update.where(self._build_condition(table, k, v))
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update = update.values(**values)
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@ -319,8 +384,12 @@ class DbPlugin(Plugin):
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:type records: list
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:param engine: Engine to be used (default: default class engine)
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:type engine: str
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:param args: Extra arguments that will be passed to ``sqlalchemy.create_engine`` (see https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to ``sqlalchemy.create_engine`` (seehttps:///docs.sqlalchemy.org/en/latest/core/engines.html)
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:param args: Extra arguments that will be passed to
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``sqlalchemy.create_engine`` (see
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https://docs.sqlalchemy.org/en/latest/core/engines.html)
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:param kwargs: Extra kwargs that will be passed to
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``sqlalchemy.create_engine``
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(see https:///docs.sqlalchemy.org/en/latest/core/engines.html)
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Example:
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@ -347,7 +416,7 @@ class DbPlugin(Plugin):
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table, engine = self._get_table(table, engine=engine, *args, **kwargs)
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delete = table.delete()
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for (k,v) in record.items():
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for (k, v) in record.items():
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delete = delete.where(self._build_condition(table, k, v))
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engine.execute(delete)
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