SQL 1. What are the types of SQL statement? Data Manipulation
... query's select list can select any columns from any of these tables. If any two of these tables have a column name in common, then you must qualify all references to these columns throughout the query with table names to avoid ambiguity. Most join queries contain WHERE clause conditions that compare ...
... query's select list can select any columns from any of these tables. If any two of these tables have a column name in common, then you must qualify all references to these columns throughout the query with table names to avoid ambiguity. Most join queries contain WHERE clause conditions that compare ...
Database Management Systems
... Syntax: select attribute-list from table-list where condition select Title from Movie where Rating = 'PG' select Name, Address from Customer select * from Movie where Genre like '%action%' select * from Movie where Rating = 'R' order by Title ...
... Syntax: select attribute-list from table-list where condition select Title from Movie where Rating = 'PG' select Name, Address from Customer select * from Movie where Genre like '%action%' select * from Movie where Rating = 'R' order by Title ...
Moving Objects Databases - Worcester Polytechnic Institute
... Observe that in order for this procedure to produce correct results, we must ensure that F’ and p are satisfied for the same tuple in the cartesian product of the FROM relations. We ensure this by including in the target list of all four queries, a key of each relation in the FROM clause. The above ...
... Observe that in order for this procedure to produce correct results, we must ensure that F’ and p are satisfied for the same tuple in the cartesian product of the FROM relations. We ensure this by including in the target list of all four queries, a key of each relation in the FROM clause. The above ...
Query Optimization
... Decision not to push rating>5 before the join is based on availability of sid index on Sailors. Cost: Selection of Reserves tuples (10 I/Os); for each, must get matching Sailors tuple (1000*1.2); total 1210 I/Os. Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke ...
... Decision not to push rating>5 before the join is based on availability of sid index on Sailors. Cost: Selection of Reserves tuples (10 I/Os); for each, must get matching Sailors tuple (1000*1.2); total 1210 I/Os. Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke ...
A Closer Look
... • 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: ...
Mini-MSDD - Relational Databases
... about the entities. The various qualities (characteristics) of the entity that are to be described are referred to as attributes For each of these attributes for each entity there is potentially a value (taken from a legal set of values that obey certain constraints or rules) There is some structure ...
... about the entities. The various qualities (characteristics) of the entity that are to be described are referred to as attributes For each of these attributes for each entity there is potentially a value (taken from a legal set of values that obey certain constraints or rules) There is some structure ...
Relational Databases and Structure Query Language (SQL)
... with “Joins” and “Relates” in ArcGIS • GeoDatabases are relational databases • Structured Query Language (SQL) is the primary language for relational databases • You’ve been using SQL statements in ArcGIS to query data ...
... with “Joins” and “Relates” in ArcGIS • GeoDatabases are relational databases • Structured Query Language (SQL) is the primary language for relational databases • You’ve been using SQL statements in ArcGIS to query data ...
The Relational Model
... Foreign key : Set of fields in one relation that is used to `refer’ to a tuple in another (or the same) relation. (Must correspond to primary key of the second relation.) Like a `logical pointer’. E.g. sid is a foreign key referring to Students: ...
... Foreign key : Set of fields in one relation that is used to `refer’ to a tuple in another (or the same) relation. (Must correspond to primary key of the second relation.) Like a `logical pointer’. E.g. sid is a foreign key referring to Students: ...
Talk slides
... Set of physical structures (i.e., indexes and views) that make similar workloads execute as fast as possible ...
... Set of physical structures (i.e., indexes and views) that make similar workloads execute as fast as possible ...
Movie
... • The above insertion, were it allowed to get through, would insert a tuple with NULL for studioName in the underlying Movie table. • However, such a tuple doesn't satisfy the condition for being in the ParamountMovie view! • Thus, it shouldn't be allowed to get into the database through the Paramou ...
... • The above insertion, were it allowed to get through, would insert a tuple with NULL for studioName in the underlying Movie table. • However, such a tuple doesn't satisfy the condition for being in the ParamountMovie view! • Thus, it shouldn't be allowed to get into the database through the Paramou ...
Indexing Relational Database Content Offline for
... required to expand the starting web page set to find navigation paths satisfying the full query, work that we perform offline. Three systems, DBXplorer, BANKS, and DISCOVER, share a similar approach: At query time, given a set of keywords, first find tuples in each relation that contain at least one ...
... required to expand the starting web page set to find navigation paths satisfying the full query, work that we perform offline. Three systems, DBXplorer, BANKS, and DISCOVER, share a similar approach: At query time, given a set of keywords, first find tuples in each relation that contain at least one ...
SQL -- Data Definition Language
... create table r (A1 D1, A2 D2, ..., An Dn, (integrity-constraint1), ...
... create table r (A1 D1, A2 D2, ..., An Dn, (integrity-constraint1), ...
Normalization
... • staffNo sName, position, salary, branch, address • branch address • address branch • branch, position salary • address, position salary ...
... • staffNo sName, position, salary, branch, address • branch address • address branch • branch, position salary • address, position salary ...
Discovery and Maintenance of Functional Dependencies by Independencies
... use a complete inference relation regarding independencies. Sawfik and Flach have investigated a special data structure for the FDs. Briefly, they start with a bottom-up analysis of the tuples and construct a negative cover, whichis a set of FIs. In the next step they use a top-down search approach. ...
... use a complete inference relation regarding independencies. Sawfik and Flach have investigated a special data structure for the FDs. Briefly, they start with a bottom-up analysis of the tuples and construct a negative cover, whichis a set of FIs. In the next step they use a top-down search approach. ...
Relational Calculus and First-Order Logic
... • the relational calculus is a specialization of first-order logic, tailored to relational databases. • straightforward: the only structuring means of relational databases are relations – each relation can be seen as an interpretation of a predicate. • there exists a declarative semantics. Relationa ...
... • the relational calculus is a specialization of first-order logic, tailored to relational databases. • straightforward: the only structuring means of relational databases are relations – each relation can be seen as an interpretation of a predicate. • there exists a declarative semantics. Relationa ...
CS122_SUMMER_2009_LECTURE_01
... Previous to the relational model, one had to write a program that traversed pointers at the physical level to extract data from a database (think like programming in assembly language) By abstracting the physical level and writing a program at the logical level instead (think like programming in Jav ...
... Previous to the relational model, one had to write a program that traversed pointers at the physical level to extract data from a database (think like programming in assembly language) By abstracting the physical level and writing a program at the logical level instead (think like programming in Jav ...
ppt
... • Why do we need NOT NULL? • What would happen if I executed these commands in this order? ...
... • Why do we need NOT NULL? • What would happen if I executed these commands in this order? ...
Title Goes Here - Binus Repository
... • To assist users in choosing a DBMS that is well suited to their needs, several performance benchmarking have ...
... • To assist users in choosing a DBMS that is well suited to their needs, several performance benchmarking have ...
Handout: Databases, and Databases in R
... If information is split across tables, we need to join it back together. The operation which does so is called a “join”, naturally enough, which in SQL shows up as a JOIN clause in SELECT, modifying the FROM. (In R, we join dataframes with the merge command; it has all the functionality of JOIN, tho ...
... If information is split across tables, we need to join it back together. The operation which does so is called a “join”, naturally enough, which in SQL shows up as a JOIN clause in SELECT, modifying the FROM. (In R, we join dataframes with the merge command; it has all the functionality of JOIN, tho ...
Chapter 6: Logical database design and the relational model
... Translate the conceptual database design into a logical database design that can be implemented on a chosen DBMS later ...
... Translate the conceptual database design into a logical database design that can be implemented on a chosen DBMS later ...