In the Choosing keys section a grammatical mistake is made where 'effect' is used instead of 'affect'.
"Deciding the column(s) that will form the keys in the definition should be a carefully considered activity as it will effect performance and data integrity."
Should be
"Deciding the column(s) that will form the keys in the definition should be a carefully considered activity as it will affect performance and data integrity."
In the Choosing keys section a grammatical mistake is made where 'effect' is used instead of 'affect'.
"Deciding the column(s) that will form the keys in the definition should be a carefully considered activity as it will effect performance and data integrity."
Should be
"Deciding the column(s) that will form the keys in the definition should be a carefully considered activity as it will affect performance and data integrity."