msilib Module¶

⚠️ REMOVED IN PYTHON 3.13: The msilib module was deprecated in Python 3.11 and removed in Python 3.13.

The msilib module creates and manipulates Microsoft Installer (.msi) files. An MSI file is a small relational database, and the module exposes it as such: databases, tables, records, views, and SQL-like queries.

It was Windows-only. On other platforms importing it raised ModuleNotFoundError.

Complexity Reference¶

Database and Views¶

Operation	Time	Space	Notes
`OpenDatabase(path, persist)`	O(1) + I/O	O(1)	Open or create an MSI database
`CreateRecord(count)`	O(1)	O(count)	Allocate a record with `count` fields
`db.OpenView(sql)`	O(1)	O(1)	Compile a query
`view.Execute(params)`	O(1)	O(1)	Run the compiled query
`view.Fetch()`	O(1)	O(f)	One row; f = field count
`view.Modify(mode, record)`	O(log n)	O(1)	Insert, update, or delete; n = table rows
`view.Close()`	O(1)	O(1)	Release the view
`db.Commit()`	O(n) + I/O	O(1)	Flush all pending changes
Full table scan	O(n)	O(f)	n `Fetch()` calls, one per row

Records¶

Operation	Time	Space	Notes
`record.GetString(field)`	O(k)	O(k)	k = string length
`record.SetString(field, value)`	O(k)	O(k)	k = string length
`record.GetInteger(field)`	O(1)	O(1)	Integer field
`record.SetInteger(field, value)`	O(1)	O(1)	Integer field
`record.SetStream(field, path)`	O(n) + I/O	O(1)	n = file size; embeds a file
`record.GetFieldCount()`	O(1)	O(1)	Number of fields
`record.ClearData()`	O(f)	O(1)	Reset all fields

Helpers¶

Operation	Time	Space	Notes
`add_data(db, table, records)`	O(r log n)	O(1)	r = records inserted
`add_tables(db, module)`	O(t)	O(1)	t = table definitions
`init_database(name, schema, ...)`	O(t) + I/O	O(1)	Create a database from a schema
`gen_uuid()`	O(1)	O(1)	New GUID string
`Directory` / `Feature` / `CAB` classes	varies	varies	Wrappers over the above

Inserts go through the installer's indexed tables, hence the O(log n) per row rather than O(1). Building a package is therefore O(r log n) in the number of rows, plus linear I/O for any embedded streams.

Reading a Table¶

import msilib

db = msilib.OpenDatabase("package.msi", msilib.MSIDBOPEN_READONLY)
view = db.OpenView("SELECT Property, Value FROM Property")   # O(1)
view.Execute(None)                                           # O(1)

# O(n) - one Fetch per row
while True:
    record = view.Fetch()
    if record is None:
        break
    print(record.GetString(1), record.GetString(2))
view.Close()

Inserting Rows¶

import msilib

db = msilib.OpenDatabase("package.msi", msilib.MSIDBOPEN_TRANSACT)

# O(r log n) - each row is inserted into an indexed table
msilib.add_data(db, "Property", [
    ("ProductName", "Example"),
    ("ProductVersion", "1.0.0"),
])

db.Commit()   # O(n) - flush to disk

Embedding a File¶

import msilib

record = msilib.CreateRecord(2)          # O(1)
record.SetString(1, "readme.txt")        # O(k)
record.SetStream(2, "docs/readme.txt")   # O(n) in file size

Removed in Python 3.13

There is no standard-library replacement. Use the WiX Toolset, or a third-party packaging tool, to build MSI installers.

Batch inserts before committing

Commit() is the expensive call. Accumulate rows and commit once rather than committing per row.

Version Notes¶

Python 3.11: deprecated (PEP 594)
Python 3.13: removed
Before 3.13: Windows-only; wrapped the Windows Installer API
All versions: query and insert complexity is governed by the installer's own table indexes