Delphi support for SQLite manifest typing

You can do this with any direct access layer to sqlite engine, without any TDataset layer.

For instance our open source wrapper http://blog.synopse.info/post/2011/07/22/SynDBSQLite3%3A-SQLite3-direct-access

In fact, unlike most SQL databases, SQLite does not restrict the type of data that may be inserted into a column based on the column's declared type. Instead, SQLite uses dynamic typing. The declared type of a column is used to determine the affinity of the column only. Direct access without the Db.pas layer allows use of this unique feature.

Your solution can lay in sqlite itself. The schema is by default not writable (you can not UPDATE sqlite_master table) but with sane knowledge and a little help of PRAGMA writable_schema=ON; you can do this. So some changes are safe, for example changing VARCHAR(N) to VARCHAR(M), sqlite doesn't care about the number in the brackets.

Step 1, your schema is limited to 30 chars

CREATE TABLE [TestTable] ([Id] INTEGER PRIMARY KEY AUTOINCREMENT,[Txt] VARCHAR(30))

The line below allows sqlite_table changes

PRAGMA writable_schema=ON;

And the following statement will change the limits to 100

Update sqlite_master set sql='CREATE TABLE [TestTable] ([Id] INTEGER PRIMARY KEY AUTOINCREMENT,[Txt] VARCHAR(100))' where tbl_name='TestTable' and type='table'

But you should be aware of what you're doing since some changes are no welcome because sqlite expects some storage format based on the information in the schema. Varchar to varchar conversion does not change the storage format

Because I wanted a really thin wrapper around the sqlite3.dll, I wrote my own, heavily based on OleVariants:

https://github.com/stijnsanders/TSQLite

It should also 'disregard' column type like you discribe, since I've added no other type checking than what the query results provide.