A database query template and metadata mapping provide an end-user to generate customized database reports via a user interface. The parameters and data available to the end-user can be modified by editing the database query template and metadata mapping without modifications of the underlying system. A database query template includes query language keywords, variables, and template-tokens and defines the metrics, dimensions, data comparisons, filters, and aggregations available to an end-user. Template tokens include restriction tokens for comparing and filtering data, options-section-tokens for defining and omitting sections of the query template, and descriptor tokens for identifying dimensions and metrics of the database. The database query template is transformed into a database query based on values input by a user. The metadata mapping associates the variables of the database query template to the database data model and can include data constraints for validation of user input.