As far as the melatonin, don't waste your money on it, because it doesn't do anything for you. You'd get just as good result, giving your child pieces of candy, or anything edible really, and telling them that it'll help them sleep, and if they believe it will, it might, just like melatonin does.
Ultimately, all of the data is stored in columns, and metadata is required to identify the columns that function as multidimensional objects. In Oracle Database, you can define a logical multidimensional model for relational tables using the OLAP Catalog or AWXML, as described in Chapter 5..2 The Relational Implementation of the Model. The relational implementation of the multidimensional data model is typically a star schema, as shown in Figure 2-2, or a snowflake schema.
PHP - Multidimensional Arrays. A multidimensional array is an array containing one or more arrays. PHP understands multidimensional arrays that are two, three, four, five, or more levels deep. However, arrays more than three levels deep are hard to manage for most people. The dimension of an array indicates the number of indices you need to select an element.