-- One-time install step: widen InvoiceNumber from varchar(14) to varchar(100).
-- Run as a login with ALTER rights on posinv (not the app's limited login).
-- Safe to re-run: each column is only altered while it is still narrower.
USE posinv;
GO

IF COL_LENGTH('dbo.InvoiceHeader', 'InvoiceNumber') < 100
    ALTER TABLE dbo.InvoiceHeader ALTER COLUMN [InvoiceNumber] varchar(100) NULL;

IF COL_LENGTH('dbo.InvoiceDetail', 'InvoiceNumber') < 100
    ALTER TABLE dbo.InvoiceDetail ALTER COLUMN [InvoiceNumber] varchar(100) NULL;
GO

SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH, IS_NULLABLE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME IN ('InvoiceHeader', 'InvoiceDetail') AND COLUMN_NAME = 'InvoiceNumber';