Ability to delete SQL records in MyLittleAdmin

[geordienz]

Newbie here. Can anyone tell me why some of my SQL tables allow manual deletion of records via MyLittleAdmin while others will not?
If it is a setting somewhere, is there any danger attached to having it set to "deletion allowed"?

TIA

[geordienz]

Discovered it was because of the lack of an Index on the tables. The tables I couldn't edit had been created via an export from MS Access.