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Published byKaela Goatley Modified over 3 years ago

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Multimedia Database Schema Design Jianguo Huo

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Outline MMDB Design Issues Multimedia Data Types Features and Similarity Functions M-Dependencies Normalization Evaluation

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MMDB Design Issues Requirements for the MMDB –Representation, storage, interpretation, composition, retrieval and delivery of diverse data types Data Model Storage structure Architecture Retrieval algorithms

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MMDB Schema Design Building blocks –Data type –Relations –Rows (tuples) –Columns –Similarity function and thresholds –Dependencies –MMDB schema Knobs –Data types, relations, similarity functions, thresholds

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Data Types Semantics of Multimedia Attributes Why not BLOB Generalized Icon –(x m, x i ) –Earcons, ticons, micon, vicons –multicons

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Features and Similarity Functions Features and Tuples comparison –Equal vs. similar Similarity Functions –Distance functions –Threshold –Combination of similarity functions Let R(z1:Z1,…, zn:Zn), v be a tuple distance function on R, t be a maximum distance threshold, x=(x1,…, xn) and y=(y1,…, yn) be two tuples in R, we say that x is similar within t to y with respect to v, denoted with x w(t) y, iff v(x, y) t.

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M-Dependencies The benefits from exploiting dependencies Classes of M-Dependencies –Type M Functional dependency (MFD) –Type M Multivalued dependency (MMD) –Type M Join dependency (MJD) –…technically MFD: Let R be a relation with attribute set U, and X, Y U. Xg1(t’) → Yg2(t’’) is a type-M functional dependency (MFD) relation if and only if for any two tuples t1 and t2 in R that have t1[X] g1(t’) t2[X], then t1[Y] g2(t’’) t2[Y], where g1 TD(X) and g2 TD(Y), whereas t’ and t’’ [0,1] are thresholds. MMD: Let R be a multimedia relation with attribute set U, and X, Y U. Xg1(t') →» Yg2(t'')[g3(t''')] is a type-M multivalued dependency (MMD) relation if and only if for any two tuples t1 and t2 in R such that t1[X] g1(t') t2[X], there also exist in R two tuples t3 and t4 with the following properties: t3[X], t4[X] [t1[X]] g1(t') t3[Y] g2(t'') t1[Y] and t4[Y] g2(t'') t2[Y] t3[R– (XY)] g3(t''') t2[R – (XY)] and t4[R – (XY)] g3(t''') t1[R – (XY)]. where g1 TD(X), g2 TD(Y) and g3 TD(R–(XY)), whereas t', t'' and t''' [0,1] are thresholds. MJD: Let R be a relation on U, and {X1,…,Xn} U, with the union of Xi’s being U. If R = PX1,g1(t1)(R) g1(t1) PX2,g2(t2)(R) g2(t2)… gn-1(tn-1) PXn,I (R), we say that R satisfies a Type-M Join Dependency (MJD), denoted by [g1(t1),…, gn-1(tn-1)][X1,..., Xn], where gi TD(Xi Xi+1) and ti [0,1] for each 1 i n-1.

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Normal Forms Dependency-based design practice Benefits Types of Normal Forms –1MNF –2MNF –3MNF –4MNF –5MNF –…technically 1MNF: We say that a multimedia database schema is in first multimedia normal form (1MNF) if each attribute A has the type of number, string or elementary generalized icon. 2MNF: We say that a multimedia database schema is in second multimedia normal form (2MNF) if it is in 1MNF and each non prime attribute A is fully dependent on the primary key. 3MNF: We say that a multimedia database schema R is in third multimedia normal form (3MNF) if it is in 2MNF and the non prime attributes are not mutually dependent. 4MNF: We say that a multimedia database schema R is in fourth multimedia normal form (4MNF) with respect to a set of multimedia dependencies D if, for every nontrivial MMD Xg1(t1) →» Yg2(t2)[g3(t3)] in D+, X is a superkey for R. 5MNF: we say that R is in 5MNF with respect to a set D of MFDs, MMDs, and MJDs if, for every nontrivial type-M join dependency [g1(t1),…, gn-1(tn-1)](X1,..., Xn) in D+, every Xi is a superkey for R.

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Term Project: MMDB Refactoring

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Project Goal To implement an usable tool to enable automatic database transformation –Improve the user interface –Improve the algorithm

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