Coverage for /var/devmt/py/dbilib_0.4.1/dbilib/_dbi_mysql.py: 100%
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« prev ^ index » next coverage.py v7.6.1, created at 2024-09-27 21:25 +0100
« prev ^ index » next coverage.py v7.6.1, created at 2024-09-27 21:25 +0100
1#!/usr/bin/env python3
2# -*- coding: utf-8 -*-
3"""
4:Purpose: This module contains the library's *MySQL* database methods
5 and attribute accessors; which are a specialised version of
6 the :class:`_dbi_base._DBIBase` class methods.
8:Platform: Linux/Windows | Python 3.10+
9:Developer: J Berendt
10:Email: support@s3dev.uk
12:Comments: n/a
14:Example:
16 For class-specific usage examples, please refer to the docstring
17 for the following classes:
19 - :class:`_DBIMySQL`
21"""
22# pylint: disable=wrong-import-order
23# Silence the spurious IDE-based error.
24# pylint: disable=import-error
26import pandas as pd
27import warnings
28from mysql.connector.errors import IntegrityError
29from sqlalchemy.exc import SQLAlchemyError
30from utils4.reporterror import reporterror
31from utils4.user_interface import ui
32# locals
33from _dbi_base import _DBIBase
36class _DBIMySQL(_DBIBase):
37 """This *private* class holds the methods and properties which are
38 used for accessing MySQL-like databases, including MariaDB.
40 Note:
41 This class is *not* designed to be interacted with directly.
43 Rather, please use the :class:`database.DBInterface` class
44 instead, as the proper interface class has an automatic switch
45 for database interfaces, based on the ``sqlalchemy.Engine``
46 object which is created from the connection string.
48 Args:
49 connstr (str): The database-specific SQLAlchemy connection
50 string.
52 :Example Use:
54 This low-level generalised class is designed to be inherited by
55 the calling/wrapping class as::
57 >>> from dbilib.database import DBInterface
59 class MyDB(DBInterface):
61 def __init__(self, connstr: str):
62 super().__init__(connstr=('mysql+mysqlconnector://'
63 '<user>:<pwd>@<host>:<port>/'
64 '<db_name>'))
66 """
68 # The __init__ method is implemented in the parent class.
70 def call_procedure(self,
71 proc: str,
72 params: list | tuple = None,
73 return_status: bool=False) -> pd.DataFrame | tuple[pd.DataFrame | bool]:
74 """Call a stored procedure, and return as a DataFrame.
76 Args:
77 proc (str): Name of the stored procedure to call.
78 params (list | tuple, optional): A list (or tuple) of
79 parameters to pass into the procedure. Defaults to None.
80 return_status (bool, optional): Return the method's success
81 status. Defaults to False.
83 Returns:
84 pd.DataFrame | tuple[pd.DataFrame | bool]:
85 If the ``return_status`` argument is True, a tuple of the
86 data and the method's return status is returned as::
88 (df, status)
90 Otherwise, only the data is returned, as a pd.DataFrame.
92 """
93 warnings.simplefilter('ignore')
94 df = pd.DataFrame()
95 success = False
96 try:
97 # Use a context manager in an attempt to alleviate the
98 # '2055 Lost Connection' and System Error 32 BrokenPipeError.
99 with self.engine.connect() as conn:
100 cur = conn.connection.cursor(buffered=True)
101 cur.callproc(proc, params)
102 result = cur.stored_results()
103 conn.connection.connection.commit()
104 cur.close()
105 df = self._result_to_df__stored(result=result)
106 success = not df.empty
107 except SQLAlchemyError as err:
108 msg = f'Error occurred while running the USP: {proc}.'
109 self._report_sa_error(msg=msg, error=err)
110 except Exception as err:
111 reporterror(error=err)
112 return (df, success) if return_status else df
114 def call_procedure_update(self,
115 proc: str,
116 params: list=None,
117 return_id: bool=False) -> bool | tuple:
118 """Call an *update* or *insert* stored procedure.
120 Note:
121 Results are *not* returned from this call, only a boolean
122 status flag and the optional last row ID.
124 If results are desired, please use the
125 :meth:~`call_procedure` method.
127 Args:
128 proc (str): Name of the stored procedure to call.
129 params (list, optional): A list of parameters to pass into
130 the USP. Defaults to None.
131 return_id (bool, optional): Return the ID of the last
132 inserted row. Defaults to False.
134 Returns:
135 bool | tuple: If ``return_id`` is False, True is
136 returned if the procedure completed successfully, otherwise
137 False. If ``return_id`` is True, a tuple containing the
138 ID of the last inserted row and the execution success flag
139 are returned as::
141 (id, success_flag)
143 """
144 try:
145 rowid = None
146 success = False
147 # Use a context manager in an attempt to alleviate the
148 # '2055 Lost Connection' and System Error 32 BrokenPipeError.
149 with self.engine.connect() as conn:
150 cur = conn.connection.cursor()
151 cur.callproc(proc, params)
152 conn.connection.connection.commit()
153 if return_id:
154 # The cur.lastrowid is zero as the mysql_insert_id()
155 # function call applied to a CALL and not the statement
156 # within the procedure. Therefore, it must be manually
157 # obtained here:
158 cur.execute('SELECT LAST_INSERT_ID()')
159 rowid = cur.fetchone()[0]
160 cur.close()
161 success = True
162 except IntegrityError as ierr:
163 # Duplicate entry: errno = 1062
164 msg = f'{self._PREFIX} {ierr}'
165 ui.print_alert(text=msg)
166 except Exception as err:
167 reporterror(err)
168 return (rowid, success) if return_id else success
170 def call_procedure_update_many(self, *args, proc: str, iterable: list | tuple) -> bool:
171 r"""Call an *update* or *insert* stored procedure for an iterable.
173 Note:
174 The arguments are passed into the USP in the following order:
176 \*args, iterable_item
178 Ensure the USP is designed to accept the iterable item as
179 the *last* parameter.
181 Args:
182 *args (str | int | float): Positional arguments to be
183 passed into the USP, in front of each iterable item.
184 Note: The parameters are passed into the USP in the
185 order received, followed by the iterable item.
186 proc (str): Name of the stored procedure to call.
187 iterable (list | tuple): List of items to be loaded into
188 the database.
190 Returns:
191 bool: True if the update was successful, otherwise False.
193 """
194 try:
195 success = False
196 with self.engine.connect() as conn:
197 cur = conn.connection.cursor()
198 for i in iterable:
199 cur.callproc(proc, [*args, i])
200 conn.connection.connection.commit()
201 cur.close()
202 success = True
203 except Exception as err:
204 reporterror(err)
205 return success
207 def call_procedure_update_raw(self, proc: str, params: list=None):
208 """Call an *update* or *insert* stored procedure, without error
209 handling.
211 .. warning::
212 This method is **unprotected**, perhaps use
213 :meth:`~call_procedure_update` instead.
215 This 'raw' method *does not* contain an error handler. It is
216 (by design) the responsibility of the caller to contain and
217 control the errors.
219 The purpose of this raw method is to enable the caller method to
220 contain and control the errors which might be generated from a
221 USP call, for example a **duplicate key** error.
223 Args:
224 proc (str): Name of the stored procedure to call.
225 params (list, optional): A list of parameters to pass into
226 the USP. Defaults to None.
228 """
229 with self._engine.connect() as conn:
230 cur = conn.connection.cursor(buffered=True)
231 cur.callproc(proc, params)
232 conn.connection.connection.commit()
233 cur.close()
235 def table_exists(self, table_name: str, verbose: bool=False) -> bool:
236 """Using the ``engine`` object, test if the given table exists.
238 Args:
239 table_name (str): Name of the table to test.
240 verbose (bool, optional): Print a message if the table does
241 not exist. Defaults to False.
243 Returns:
244 bool: True if the given table exists, otherwise False.
246 """
247 params = {'schema': self._engine.url.database,
248 'table_name': table_name}
249 stmt = ('select count(*) from information_schema.tables '
250 'where table_schema = :schema '
251 'and table_name = :table_name')
252 exists = bool(self.execute_query(stmt, params=params, raw=True)[0][0])
253 if (not exists) & verbose:
254 msg = f'Table does not exist: {self._engine.url.database}.{table_name}'
255 ui.print_warning(text=msg)
256 return exists