nov09
... create meaningful query. • One-to-many is most common – “Each city has one or more employees.” – Now, query will return 3 results instead of 6: ...
... create meaningful query. • One-to-many is most common – “Each city has one or more employees.” – Now, query will return 3 results instead of 6: ...
gatlinburgh - Animated DataBase Courseware
... • Construction: allows student to break SQL queries into parts and quickly access the results. • Visualization: Associating code that students already know with code they are unfamiliar. ...
... • Construction: allows student to break SQL queries into parts and quickly access the results. • Visualization: Associating code that students already know with code they are unfamiliar. ...
Database Management Systems
... a. R is defined as a set of tuples b. Tuples in R do not have any particular order c. In file, records are physically stored on disk so there is an order among the records d. Many logical models can bed used to sort records in R using SSN, name, age 2. Ordering of values within a tuple a. At logical ...
... a. R is defined as a set of tuples b. Tuples in R do not have any particular order c. In file, records are physically stored on disk so there is an order among the records d. Many logical models can bed used to sort records in R using SSN, name, age 2. Ordering of values within a tuple a. At logical ...
Lecture 6 Data Model Design
... the basis for deriving a relational database – Primary keys allows entities to be expressed as tables that contain data – A database is a collection of tables – Tables are assigned the same name as the entity – Each table has columns that correspond to attributes – each column has a unique name – Ea ...
... the basis for deriving a relational database – Primary keys allows entities to be expressed as tables that contain data – A database is a collection of tables – Tables are assigned the same name as the entity – Each table has columns that correspond to attributes – each column has a unique name – Ea ...
IT360 6-week Exam Review Sheet Introduction to databases 1.
... • Decomposition into relations that are in Boyce-Codd Normal Form e. Multivalued dependencies (not required for exam) ...
... • Decomposition into relations that are in Boyce-Codd Normal Form e. Multivalued dependencies (not required for exam) ...
ppt
... 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 ...
select
... • SQL allows a subquery expression to be used in the from clause • Find the average instructors’ salaries of those departments where the average salary is greater than $42,000. – select dept_name, avg_salary from (select dept_name, avg (salary) as avg_salary from instructor group by dept_name) where ...
... • SQL allows a subquery expression to be used in the from clause • Find the average instructors’ salaries of those departments where the average salary is greater than $42,000. – select dept_name, avg_salary from (select dept_name, avg (salary) as avg_salary from instructor group by dept_name) where ...
Performance Optimization
... * Large Table/Small table Joins : Joins that involve three or more small tables and one large table ...
... * Large Table/Small table Joins : Joins that involve three or more small tables and one large table ...
Updated sql slides
... 3. Select one tuple for every group (and apply aggregation) SELECT can have (1) grouped attributes or (2) aggregates. ...
... 3. Select one tuple for every group (and apply aggregation) SELECT can have (1) grouped attributes or (2) aggregates. ...
Prince Sultan University - CS 340 Database Management System
... B. Database system concepts and architecture - Data models, schemas, and instances - Three-schema architecture and data independence - Database languages and interfaces - The database system environment - Centralized and client/server architectures for DBMSs - Classification of DBMSs C. Data modelin ...
... B. Database system concepts and architecture - Data models, schemas, and instances - Three-schema architecture and data independence - Database languages and interfaces - The database system environment - Centralized and client/server architectures for DBMSs - Classification of DBMSs C. Data modelin ...
doi
... ries: 1) work based on established linguistic theories which are modified and/or extended such as [9-12]; 2) new ad hoc but efficient semantics that are not based on established linguistic theories. Examples are quoted by [2]. Some recent works are [13-15]. Our approach falls into category 2) and is ...
... ries: 1) work based on established linguistic theories which are modified and/or extended such as [9-12]; 2) new ad hoc but efficient semantics that are not based on established linguistic theories. Examples are quoted by [2]. Some recent works are [13-15]. Our approach falls into category 2) and is ...
database administration
... • Locking strategy. Does the application hold the wrong type of locks, or does it hold the correct type of locks for too long? • COMMIT strategy. Does each application program issue SQL COMMIT statements to minimize the impact of locking? ...
... • Locking strategy. Does the application hold the wrong type of locks, or does it hold the correct type of locks for too long? • COMMIT strategy. Does each application program issue SQL COMMIT statements to minimize the impact of locking? ...
Database Systems
... Two records (rows) are different if and only if their primary keys are different Composite primary key – composed by several columns ...
... Two records (rows) are different if and only if their primary keys are different Composite primary key – composed by several columns ...
Lecture 13 ppt
... • Data is striped over disks, and a parity disk for redundancy • For n disks, we split the data in n-1 parts • Each part is stored on a disk ...
... • Data is striped over disks, and a parity disk for redundancy • For n disks, we split the data in n-1 parts • Each part is stored on a disk ...
info - T5
... • Once the ERD is completed, it can be translated from a conceptual logical schema into the formal data model required by the DBMS • Most database installations are based on the relational data model ...
... • Once the ERD is completed, it can be translated from a conceptual logical schema into the formal data model required by the DBMS • Most database installations are based on the relational data model ...
nov10
... • Use “in” when you want to select among several possible values. Has the same effect as “or” – Select * from Employee where Location in (“Dublin”, “Chicago”); ...
... • Use “in” when you want to select among several possible values. Has the same effect as “or” – Select * from Employee where Location in (“Dublin”, “Chicago”); ...
ppt
... Select the first record (in sort order) among all buffer pages Write the record to the output buffer. If the output buffer is full write it to disk. Delete the record from its input buffer page. If the buffer page becomes empty then read the next block (if any) of the run into the buffer. ...
... Select the first record (in sort order) among all buffer pages Write the record to the output buffer. If the output buffer is full write it to disk. Delete the record from its input buffer page. If the buffer page becomes empty then read the next block (if any) of the run into the buffer. ...
What is a “database”? - Regis University: Academic Web Server for
... Pronounced either "S, Q, L" or "sequel" Widely used standard set of commands and syntax for doing things with Relational DBMSs Used especially for query and retrieval Includes commands for defining Relational DBs, conducting transactions, storing data, etc. Each Relational DBMS also has additional f ...
... Pronounced either "S, Q, L" or "sequel" Widely used standard set of commands and syntax for doing things with Relational DBMSs Used especially for query and retrieval Includes commands for defining Relational DBs, conducting transactions, storing data, etc. Each Relational DBMS also has additional f ...
web-db
... outside of the database and is represented in it Describes the properties of a particular entity ...
... outside of the database and is represented in it Describes the properties of a particular entity ...
The SQL Query Language COS 597A: Principles of Database and Information Systems
... Example of Conceptual Evaluation ...
... Example of Conceptual Evaluation ...
R - Kansas State University - Laboratory for Knowledge Discovery in
... dropped relation from the database. The alter table command is used to add attributes to an existing relation: alter table r add A D where A is the name of the attribute to be added to relation r and D is the domain of A. All tuples in the relation are assigned null as the value for the new attr ...
... dropped relation from the database. The alter table command is used to add attributes to an existing relation: alter table r add A D where A is the name of the attribute to be added to relation r and D is the domain of A. All tuples in the relation are assigned null as the value for the new attr ...
Chapter 1 Introduction to DBMS Implementation
... existence of an index can make one plan much faster than another. 2. The execution engine, which has the responsibility for executing each of the steps in the chosen query plan. The execution engine interacts with most of the other components of the DBMS, either directly or through the buffers. It m ...
... existence of an index can make one plan much faster than another. 2. The execution engine, which has the responsibility for executing each of the steps in the chosen query plan. The execution engine interacts with most of the other components of the DBMS, either directly or through the buffers. It m ...
IS 331 Database Design, Management and Applications Course
... Completion of a 100-level GUR course in computing, such as IS118 or CS101 or CS104 or CS113. (It is also assumed that students have some basic familiarity with Microsoft Office (2007 or 2010), particularly Microsoft Access.) ...
... Completion of a 100-level GUR course in computing, such as IS118 or CS101 or CS104 or CS113. (It is also assumed that students have some basic familiarity with Microsoft Office (2007 or 2010), particularly Microsoft Access.) ...