This book constitutes revised selected papers from the workshops of the 5thampampnbspAsiaPacific Web and WebAge Information Management International Joint Conference on Web and Big DataampampnbspAPWebWAIM 2021ampampnbspThe Fourth International Workshop on Knowledge Graph Management and Applications KGMA 2021 TheampampnbspThird International Workshop on Semistructured Big Data Management and ApplicationampampnbspSemiBDMA 2021 and TheampampnbspSecond International Workshop on Deep Learning in Largescale Unstructured Data Analytics DeepLUDA 2021 held inampampnbspGuangzhou China in August 2021.ampampnbspDue to the COVID19 pandemic the conference was held online.ampampnbspThe 11 papers were thoroughly reviewed and selected from the 28 submissions and present recent research onampampnbspthe theory design and implementation of data management systems.