The paper provides a comprehensive survey of approaches to automatic schema matching, a fundamental operation in various database application domains such as data integration, E-business, data warehousing, and semantic query processing. Currently, schema matching is often performed manually, which is tedious, time-consuming, and error-prone. The authors present a taxonomy that categorizes existing approaches into schema-level, instance-level, element-level, structure-level, language-based, and constraint-based matchers. They review previous match implementations, highlighting their coverage within the solution space. The paper aims to be useful for comparing different schema matching approaches, developing new algorithms, and implementing schema matching components. The introduction motivates the importance of schema matching through examples in schema integration, data warehouses, E-commerce, and semantic query processing. The paper also defines the match operator and describes a high-level architecture for implementing it, providing a detailed classification of automatic schema matching methods.The paper provides a comprehensive survey of approaches to automatic schema matching, a fundamental operation in various database application domains such as data integration, E-business, data warehousing, and semantic query processing. Currently, schema matching is often performed manually, which is tedious, time-consuming, and error-prone. The authors present a taxonomy that categorizes existing approaches into schema-level, instance-level, element-level, structure-level, language-based, and constraint-based matchers. They review previous match implementations, highlighting their coverage within the solution space. The paper aims to be useful for comparing different schema matching approaches, developing new algorithms, and implementing schema matching components. The introduction motivates the importance of schema matching through examples in schema integration, data warehouses, E-commerce, and semantic query processing. The paper also defines the match operator and describes a high-level architecture for implementing it, providing a detailed classification of automatic schema matching methods.