✨ Add option to truncate existing tables before inserting data

Author: techouse

README.md

@@ -59,11 +59,13 @@ Options:
                                   UPDATE will update existing rows; IGNORE
                                   will ignore insert errors. Defaults to
                                   IGNORE.
+  -E, --mysql-truncate-tables     Truncates existing tables before inserting
+                                  data.
   --mysql-integer-type TEXT       MySQL default integer field type. Defaults
                                   to INT(11).
   --mysql-string-type TEXT        MySQL default string field type. Defaults to
                                   VARCHAR(255).
-  --mysql-text-type [MEDIUMTEXT|TINYTEXT|TEXT|LONGTEXT]
+  --mysql-text-type [MEDIUMTEXT|TEXT|TINYTEXT|LONGTEXT]
                                   MySQL default text field type. Defaults to
                                   TEXT.
   --mysql-charset TEXT            MySQL database and table character set

sqlite3_to_mysql/__version__.py

@@ -2,7 +2,7 @@
 __title__ = "sqlite3-to-mysql"
 __description__ = "A simple Python tool to transfer data from SQLite 3 to MySQL"
 __url__ = "https://github.com/techouse/sqlite3-to-mysql"
-__version__ = "1.4.14"
+__version__ = "1.4.15"
 __author__ = "Klemen Tusar"
 __author_email__ = "techouse@gmail.com"
 __license__ = "MIT"

sqlite3_to_mysql/cli.py

@@ -73,6 +73,12 @@
     help="MySQL insert method. DEFAULT will throw errors when encountering duplicate records; "
     "UPDATE will update existing rows; IGNORE will ignore insert errors. Defaults to IGNORE.",
 )
+@click.option(
+    "-E",
+    "--mysql-truncate-tables",
+    is_flag=True,
+    help="Truncates existing tables before inserting data.",
+)
 @click.option(
     "--mysql-integer-type",
     default="INT(11)",
@@ -140,6 +146,7 @@ def cli(
     mysql_port,
     skip_ssl,
     mysql_insert_method,
+    mysql_truncate_tables,
     mysql_integer_type,
     mysql_string_type,
     mysql_text_type,
@@ -181,6 +188,7 @@ def cli(
             mysql_port=mysql_port,
             mysql_ssl_disabled=skip_ssl,
             mysql_insert_method=mysql_insert_method,
+            mysql_truncate_tables=mysql_truncate_tables,
             mysql_integer_type=mysql_integer_type,
             mysql_string_type=mysql_string_type,
             mysql_text_type=mysql_text_type,

sqlite3_to_mysql/debug_info.py

@@ -8,7 +8,7 @@
 import platform
 import sqlite3
 import sys
-from distutils.spawn import find_executable
+from distutils.spawn import find_executable  # pylint: disable=W0402
 from subprocess import check_output
 
 import click

sqlite3_to_mysql/transporter.py

@@ -102,6 +102,8 @@ def __init__(self, **kwargs):
         if self._mysql_insert_method not in MYSQL_INSERT_METHOD:
             self._mysql_insert_method = "IGNORE"
 
+        self._mysql_truncate_tables = kwargs.get("mysql_truncate_tables") or False
+
         self._mysql_integer_type = str(
             kwargs.get("mysql_integer_type") or "INT(11)"
         ).upper()
@@ -385,6 +387,25 @@ def _create_table(self, table_name, transfer_rowid=False):
             )
             raise
 
+    def _truncate_table(self, table_name):
+        self._mysql_cur.execute(
+            """
+            SELECT `TABLE_NAME`
+            FROM `INFORMATION_SCHEMA`.`TABLES`
+            WHERE `TABLE_SCHEMA` = %s
+            AND `TABLE_NAME` = %s
+            LIMIT 1
+            """,
+            (self._mysql_database, safe_identifier_length(table_name)),
+        )
+        if len(self._mysql_cur.fetchall()) > 0:
+            self._logger.info("Truncating table %s", safe_identifier_length(table_name))
+            self._mysql_cur.execute(
+                "TRUNCATE TABLE `{}`".format(
+                    safe_identifier_length(table_name),
+                ),
+            )
+
     def _add_indices(self, table_name):
         self._sqlite_cur.execute('PRAGMA table_info("{}")'.format(table_name))
         table_columns = {}
@@ -678,6 +699,10 @@ def transfer(self):
                 # create the table
                 self._create_table(table["name"], transfer_rowid=transfer_rowid)
 
+                # truncate the table on request
+                if self._mysql_truncate_tables:
+                    self._truncate_table(table["name"])
+
                 # get the size of the data
                 self._sqlite_cur.execute(
                     'SELECT COUNT(*) AS total_records FROM "{}"'.format(table["name"])