In real world, data are stored in multiple relational databases. many problems like expensive join operation and semantic losses in classifying objects stored in multiple tables (relations) involves. Multi relational classification is the process of building a classifier based on information stored in multiple relations This approach has been developed for handling the structured data such that RDBMS. This will provides the mining in multiple tables' directly. This paper provides an insight into various relational database-based classification methods of MRDM. Their characteristics and comparisons in detail have also been provided. © Research India Publications.