CS655-HessahAlsaaran-DBonS3

To all replicas but they can be out of order too weak

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Unformatted text preview: . 1- to- many relationship Ê༌  Each tuple is mapped to a group of rows (for each attribute) with the same row id. Child Ê༌  Why? A row can have multiple columns. Ê༌  Tablet size is 100 MB Ê༌  Row groups are not split. Ê༌  Distributed to all nodes. Ê༌  Exploit the entity- relationship diagram in constructing the •  Typically, child entities have more tuples than its parents. •  Joining a parent and a child can result in different number of tuples depending on the parent: •  Assuming that a library has more copies than the number of copies per book: library- copy grouping may be larger than book- copy grouping. •  Parents that have larger number of child tuples could be treated specially (dominant parent). records (clustering). Figure 1 from (Johnson, 2009) 25 Query Evaluation Entity- Relationship Diagram Parents 26 Row ids = (letter representing table)+ (primary key) Examples: Pxxx, Lxxx, Bxxx For Copy: the dominant parent is Library: Lxxx- Byyy- Czzz Advantage: Since rows are kept in order à༎ copy tuples will be grouped by library. In addition, the library’s important attributes are inserted with the first copy tuple in each tablet. Child Ê༌  Example: Ê༌  All Seattle libraries that have loaned books in poor condition to blue- eyed patron after January 1, 2008. Ê༌  SQL Query: SQL query from page 22 (Johnson, 2009)...
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