View PDF - CiteSeerX
... what exactly an \ontology" is. In particular, there is a question as to whether \exemplars," the individual items lling an ontological de nition count as part of the ontology. Thus, for example, does a knowledge base containing information about thousands of cities and the countries they are found ...
... what exactly an \ontology" is. In particular, there is a question as to whether \exemplars," the individual items lling an ontological de nition count as part of the ontology. Thus, for example, does a knowledge base containing information about thousands of cities and the countries they are found ...
Visual Database Creation with MySQL Workbench
... Relationships • 1:1 relationships. Primary key for one of the tables is included as foreign key in the other table • 1:n relationships. Primary key of the table in the ’1′ side is added as foreign key in the table in the ‘n’ side • n:m relationships. A new table ( join table) is created. The primar ...
... Relationships • 1:1 relationships. Primary key for one of the tables is included as foreign key in the other table • 1:n relationships. Primary key of the table in the ’1′ side is added as foreign key in the table in the ‘n’ side • n:m relationships. A new table ( join table) is created. The primar ...
ORMs and Hibernate - Data Systems Group
... Specified using metadata For example, a row of the Employee table will correspond to an instance of the Employee object within the application Mappings are often not isomorphic Sophisticated ORMs such as Hibernate and LINQ permit object models that differ substantially from the underlying re ...
... Specified using metadata For example, a row of the Employee table will correspond to an instance of the Employee object within the application Mappings are often not isomorphic Sophisticated ORMs such as Hibernate and LINQ permit object models that differ substantially from the underlying re ...
Views-basics
... (e.g. TotSal before) a grouped view may never be joined with a base table or another view ...
... (e.g. TotSal before) a grouped view may never be joined with a base table or another view ...
DATA STREAMS AND DATABASES
... Stream data changes continually! Thus, results of queries against a stream also change continually. ¤ Such queries are called continuous queries. ¤ Register continuous queries with the database server. ¤ As stream data changes, DB can incrementally update and output query results efficiently. ...
... Stream data changes continually! Thus, results of queries against a stream also change continually. ¤ Such queries are called continuous queries. ¤ Register continuous queries with the database server. ¤ As stream data changes, DB can incrementally update and output query results efficiently. ...
Chapter 13: Query Optimization
... else for each non-empty subset S1 of S such that S1 ≠ S P1= findbestplan(S1) P2= findbestplan(S - S1) A = best algorithm for joining results of P1 and P2 cost = P1.cost + P2.cost + cost of A if cost < bestplan[S].cost bestplan[S].cost = cost bestplan[S].plan = “execute P1.plan; execute P2.plan; join ...
... else for each non-empty subset S1 of S such that S1 ≠ S P1= findbestplan(S1) P2= findbestplan(S - S1) A = best algorithm for joining results of P1 and P2 cost = P1.cost + P2.cost + cost of A if cost < bestplan[S].cost bestplan[S].cost = cost bestplan[S].plan = “execute P1.plan; execute P2.plan; join ...
Translation of the data flow query language Free, Nancy C.
... Database System (MOBS). The MDBS is a database system that can effectively support multiple data models and their corresponding data manipulation languages. The problem was the MDBS interfaces are text-based, and not very user-friendly. The approach taken to solve this interface problem wsas to desi ...
... Database System (MOBS). The MDBS is a database system that can effectively support multiple data models and their corresponding data manipulation languages. The problem was the MDBS interfaces are text-based, and not very user-friendly. The approach taken to solve this interface problem wsas to desi ...
item_name, color
... The for clause within the pivot clause specifies what values from the attribute color should appear as attribute names in the pivot result. The values for the newly created attributes are specified to come from the attribute quantity, and the aggregate function specifies how the values should be com ...
... The for clause within the pivot clause specifies what values from the attribute color should appear as attribute names in the pivot result. The values for the newly created attributes are specified to come from the attribute quantity, and the aggregate function specifies how the values should be com ...
Universitatea POLITEHNICA din Bucuresti
... activities during the semester and 50% out of final examination is required. c) Final scoring: According to the “Graduating Regulations”, the final score is obtained rounding overall score, if minimal passing requirements are fulfilled. 6. BENCHMARKING The lectures are presented using multimedia fac ...
... activities during the semester and 50% out of final examination is required. c) Final scoring: According to the “Graduating Regulations”, the final score is obtained rounding overall score, if minimal passing requirements are fulfilled. 6. BENCHMARKING The lectures are presented using multimedia fac ...
Lecture slides
... The Data Definition Language (DDL) part of SQL permits database tables to be created or deleted. We can also define indexes (keys), specify links between tables, and impose constraints between database tables. The most important DDL statements in SQL are: ...
... The Data Definition Language (DDL) part of SQL permits database tables to be created or deleted. We can also define indexes (keys), specify links between tables, and impose constraints between database tables. The most important DDL statements in SQL are: ...
security of database systems - Computer Science and Engineering
... MODIFY privileges on R: This gives the account the capability to modify tuples of R. In SQL this privilege is further divided into UPDATE, DELETE, and INSERT privileges to apply the corresponding SQL command to R. In addition, both the INSERT and UPDATE privileges can specify that only certain att ...
... MODIFY privileges on R: This gives the account the capability to modify tuples of R. In SQL this privilege is further divided into UPDATE, DELETE, and INSERT privileges to apply the corresponding SQL command to R. In addition, both the INSERT and UPDATE privileges can specify that only certain att ...
(referential integrity, SQL). - Purchase College Faculty Web Server
... Consider orders by customer • what information goes with the order and • what information goes with the customer ...
... Consider orders by customer • what information goes with the order and • what information goes with the customer ...
ppt - Information Systems
... select item-name, color, size, sum(number), grouping(item-name) as item-name-flag, grouping(color) as color-flag, grouping(size) as size-flag, from sales group by cube(item-name, color, size) Can use the function decode() in the select clause to replace such nulls by a value such as all E.g. rep ...
... select item-name, color, size, sum(number), grouping(item-name) as item-name-flag, grouping(color) as color-flag, grouping(size) as size-flag, from sales group by cube(item-name, color, size) Can use the function decode() in the select clause to replace such nulls by a value such as all E.g. rep ...
Chapter 2 Notes
... • Concurrent (interleaved) execution of a set of transactions offers performance benefits, but might not be correct. • Example: Two students execute the course registration transaction at about the same time (cur_reg is the number of current registrants) T1: read(cur_reg : 29) T2: ...
... • Concurrent (interleaved) execution of a set of transactions offers performance benefits, but might not be correct. • Example: Two students execute the course registration transaction at about the same time (cur_reg is the number of current registrants) T1: read(cur_reg : 29) T2: ...
Introduction to Database Principles http://cbb.sjtu.edu.cn
... that do not fit into the traditional data processing framework Naïve users (普通用户) – invoke one of the permanent applications that have been written previously Persons accessing the database over the web, bank tellers, clerical staff ...
... that do not fit into the traditional data processing framework Naïve users (普通用户) – invoke one of the permanent applications that have been written previously Persons accessing the database over the web, bank tellers, clerical staff ...
CIS 8040 – Fundamentals of Database Management Systems
... 3. Think about a data set you have worked with recently, and try to derive a set of functional dependencies that correspond to it. What assumptions did you have to make in modeling your data in this way? ...
... 3. Think about a data set you have worked with recently, and try to derive a set of functional dependencies that correspond to it. What assumptions did you have to make in modeling your data in this way? ...
