Database management
... A request for data We need to specify where the data is located: the tables that contain the information. what conditions our data must satisfy: a set of conditions on the rows of the table involved ...
... A request for data We need to specify where the data is located: the tables that contain the information. what conditions our data must satisfy: a set of conditions on the rows of the table involved ...
Applications of the Join Operation in the REA Data Model
... that takes place next is based on the data field(s) and the join condition using any of the θ operators. The self-join is performed when the relationship between records on a set of specific data fields in that table is of interest (e.g., we may be interested in the customer’s purchasing behavior af ...
... that takes place next is based on the data field(s) and the join condition using any of the θ operators. The self-join is performed when the relationship between records on a set of specific data fields in that table is of interest (e.g., we may be interested in the customer’s purchasing behavior af ...
Chapter 3 - Spatial Database Group
... • Date constants and functions are not standard Example 7 (Access) SELECT FacFirstName, FacLastName, FacHireDate FROM Faculty WHERE FacHireDate BETWEEN #1/1/1994# AND #12/31/1995# Example 7 (Oracle) SELECT FacFirstName, FacLastName, FacHireDate FROM Faculty WHERE FacHireDate BETWEEN '1-Jan-1994' AND ...
... • Date constants and functions are not standard Example 7 (Access) SELECT FacFirstName, FacLastName, FacHireDate FROM Faculty WHERE FacHireDate BETWEEN #1/1/1994# AND #12/31/1995# Example 7 (Oracle) SELECT FacFirstName, FacLastName, FacHireDate FROM Faculty WHERE FacHireDate BETWEEN '1-Jan-1994' AND ...
SQLIII
... Sometimes better to execute parts of application inside the database system • more efficient, minimize the amount of data transferred • can be reused by other users Stored Procedure: a program that uses a single SQL statement and executed at the database server ...
... Sometimes better to execute parts of application inside the database system • more efficient, minimize the amount of data transferred • can be reused by other users Stored Procedure: a program that uses a single SQL statement and executed at the database server ...
Structured Query Language for Ecological Databases
... from yourtable where the “name” field in the two tables match. DISTINCT means that if the same age and address shows up in multiple rows, only the first instance will be displayed. ...
... from yourtable where the “name” field in the two tables match. DISTINCT means that if the same age and address shows up in multiple rows, only the first instance will be displayed. ...
Physical Database Design - NUS School of Computing
... Indexes can be used to improve data access performance, to enforce uniqueness, or to control data distribution. Indexes may be clustered or non clustered, unique or non unique, or concatenated. Testing and trial-and-error during production may indicate other index choices. A table’s indexes ...
... Indexes can be used to improve data access performance, to enforce uniqueness, or to control data distribution. Indexes may be clustered or non clustered, unique or non unique, or concatenated. Testing and trial-and-error during production may indicate other index choices. A table’s indexes ...
Lecture 3: Business Intelligence: OLAP, Data Warehouse, and Column Store 1
... • With sequential reads considered, analysis changes: may be best to divide buffers evenly between R and S. ...
... • With sequential reads considered, analysis changes: may be best to divide buffers evenly between R and S. ...
Chapter 8 - Spatial Database Group
... Rule 6: Volatile tables (lots of insertions and deletions) should not have many indexes. Rule 7: Stable columns with few values are good candidates for bitmap indexes if the columns appear in WHERE conditions. Rule 8: Avoid indexes on combinations of columns. Most optimization components can use mul ...
... Rule 6: Volatile tables (lots of insertions and deletions) should not have many indexes. Rule 7: Stable columns with few values are good candidates for bitmap indexes if the columns appear in WHERE conditions. Rule 8: Avoid indexes on combinations of columns. Most optimization components can use mul ...
All Powder Board and Ski
... In most businesses, only one customer per order, so do not key it. For a given customer, can there ever be more than one order? If yes, then key OrderID, otherwise, do not key it. All businesses hope to get more than one order from a customer, so OrderID must be key. Underline it. Since OrderID is t ...
... In most businesses, only one customer per order, so do not key it. For a given customer, can there ever be more than one order? If yes, then key OrderID, otherwise, do not key it. All businesses hope to get more than one order from a customer, so OrderID must be key. Underline it. Since OrderID is t ...
SQL QUERY EVALUATION
... (Can’t add to MySQL easily, since it doesn’t use relational algebra as a query-plan representation…) ...
... (Can’t add to MySQL easily, since it doesn’t use relational algebra as a query-plan representation…) ...
2015 WinGap Conference
... You can build the query by navigating through the list of dbo tables, selecting the table and then selecting the field names from the columns box ...
... You can build the query by navigating through the list of dbo tables, selecting the table and then selecting the field names from the columns box ...
Introduction to the Relational Model and SQL
... contents (database state) must satisfy in addition to the basic structure prescribed by the columns. • Constraints are declared as part of the database schema. • More than one key can be declared for a table More keys? One could, for example, discuss whether DNAME should also be a key (in addition t ...
... contents (database state) must satisfy in addition to the basic structure prescribed by the columns. • Constraints are declared as part of the database schema. • More than one key can be declared for a table More keys? One could, for example, discuss whether DNAME should also be a key (in addition t ...
An Introduction to SQL
... For each column in a table, the type of data that the column will store must be specified The exact list of data types available in different implementations of SQL varies ...
... For each column in a table, the type of data that the column will store must be specified The exact list of data types available in different implementations of SQL varies ...
Week 7 Table Analysis
... Changing values in the database is easier It “insulates” information – it is easier to retain important data Many operations are easier to code ...
... Changing values in the database is easier It “insulates” information – it is easier to retain important data Many operations are easier to code ...
Query - NCNU Moodle 課程
... • To indicate AND criteria in an Access query, place both criteria in the same Criteria row of the design grid; to indicate OR criteria, place criteria on separate Criteria rows of the design grid • To create a computed field in Access, enter expression in the desired column of design grid • To use ...
... • To indicate AND criteria in an Access query, place both criteria in the same Criteria row of the design grid; to indicate OR criteria, place criteria on separate Criteria rows of the design grid • To create a computed field in Access, enter expression in the desired column of design grid • To use ...
SQL Tuning - Ohio Oracle Users Group
... select executions, disk_reads, rows_processed, sorts, sql_text from v$sqlarea where disk_reads > 3000 order by disk_reads DESC; Look for high resource consumers DISK_READS EXECUTIONS SORTS ...
... select executions, disk_reads, rows_processed, sorts, sql_text from v$sqlarea where disk_reads > 3000 order by disk_reads DESC; Look for high resource consumers DISK_READS EXECUTIONS SORTS ...
Normalizing Database Files
... Right-click top field>Insert Column Change Data Type to int (or something else appropriate) Right-click this new column>Set Primary Key Set (Is Identity) to Yes in Column Properties Set Identity Seed to a value large enough so all current and expected rows will have same number of digits in their ke ...
... Right-click top field>Insert Column Change Data Type to int (or something else appropriate) Right-click this new column>Set Primary Key Set (Is Identity) to Yes in Column Properties Set Identity Seed to a value large enough so all current and expected rows will have same number of digits in their ke ...
TSQL and XML Enhancements
... Use new built-in functions to retrieve error-number, message, severity Re-raise original exception or raise an alt ...
... Use new built-in functions to retrieve error-number, message, severity Re-raise original exception or raise an alt ...
Concepts of Database Management Sixth Edition
... upper pane of Query window To make the same change to all records that satisfy certain criteria, use an update query To delete all records that satisfy certain criteria, use a delete query To save the results of a query as a table, use a make-table query Relational algebra is a theoretical method of ...
... upper pane of Query window To make the same change to all records that satisfy certain criteria, use an update query To delete all records that satisfy certain criteria, use a delete query To save the results of a query as a table, use a make-table query Relational algebra is a theoretical method of ...
Types of Queries - Information Technology
... 3.0 or higher?” or “Which students are taking an English course?” When creating a query, the names of the fields, the table associated with the fields, and the criteria to use for the query are specified. With Microsoft Access queries, it is possible to: Focus on only information needed by display ...
... 3.0 or higher?” or “Which students are taking an English course?” When creating a query, the names of the fields, the table associated with the fields, and the criteria to use for the query are specified. With Microsoft Access queries, it is possible to: Focus on only information needed by display ...
Access Project 2
... Unless specified, Access assumes that the criteria you enter involves equality or an exact match (ie. =, LIKE) The order of the greater than or equal to (>=) and less than or equal to (<=) operators is fixed; they cannot be reversed. Comparison operators are used with Numeric and Text data. ...
... Unless specified, Access assumes that the criteria you enter involves equality or an exact match (ie. =, LIKE) The order of the greater than or equal to (>=) and less than or equal to (<=) operators is fixed; they cannot be reversed. Comparison operators are used with Numeric and Text data. ...
sql_i
... Conditions on Grouped Data Use HAVING to select row that satisfy some condition on grouped data You can still use WHERE clause to select rows according to some condition ...
... Conditions on Grouped Data Use HAVING to select row that satisfy some condition on grouped data You can still use WHERE clause to select rows according to some condition ...
Set Predicates in SQL: Enabling Set
... on attribute skill in each group forming a set. The problem is that the current GROUP BY clause can only do scalar value comparison by an accompanying HAVING clause. For instance, aggregate functions SUM/COUNT/AVG/MAX produce a single numeric value, which is compared to a literal or another single ...
... on attribute skill in each group forming a set. The problem is that the current GROUP BY clause can only do scalar value comparison by an accompanying HAVING clause. For instance, aggregate functions SUM/COUNT/AVG/MAX produce a single numeric value, which is compared to a literal or another single ...
Database Systems: Design, Implementation, and Management
... • Used when tables have no common attributes • Returns only rows that meet the join condition – Typically includes equality comparison expression of two columns ...
... • Used when tables have no common attributes • Returns only rows that meet the join condition – Typically includes equality comparison expression of two columns ...