SQL Constraints and Triggers

Aug 07, 2012

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2/19. . . Integrity Constraints. An integrity constraint (IC) describes conditions that every legal instance of a relation must satisfy.Inserts/deletes/updates that violate IC's are disallowed.Can be used to ensure application semantics (e.g., sid is a key), or prevent inconsistencies (e.g., snam

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SQL Constraints and Triggers

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Database Systems I SQL Constraints and Triggers

Database Systems I SQL Constraints and Triggers. Integrity Constraints. An integrity constraint (IC) describes conditions that every legal instance of a relation must satisfy. Inserts/deletes/updates that violate IC’s are disallowed.

467 views • 19 slides

SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers. Chapter 5. R1. Example Instances. S1. We will use these instances of the Sailors and Reserves relations in our examples. If the key for the Reserves relation contained only the attributes sid and bid , how would the semantics differ?. S2.

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SQL Triggers

SQL Triggers. Jeffrey P. Landry University of South Alabama. Triggers. A trigger is procedural SQL code automatically invoked by the DBMS upon the occurrence of a given database manipulation event associated with INSERT, UPDATE, and DELETE events associated with a specific table .

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SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers. Chapter 5. SQL . Data Manipulation Language (DML): subset of SQL which allows users to create queries and to insert , delete and modify rows .

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Constraints & Triggers

Constraints & Triggers. Active elements: executes as appropriate Database integrity: insert/delete/update # of students > 3.0 < 30% name should not have numbers or special characters We must have basic data (name, gender) about students who enroll in courses

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Constraints & Triggers

Constraints & Triggers. Triggers – Introduction. Triggers. Triggers “Event-Condition-Action Rules” When event occurs, check condition ; if true, do action 1) Move monitoring logic from apps into DBMS 2) Enforce constraints Beyond what constraint system supports

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SQL: Constraints and Triggers

SQL: Constraints and Triggers. Chapter 6 Ullman and Widom Certain properties we’d like our database to hold Modification of the database may break these properties Build handlers into the database definition. Keys: Fundamental Constraint. In the CREATE TABLE statement, use:

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SQL Constraints and Triggers

SQL Constraints and Triggers. General Constraints. Attribute-based CHECK defined in the declaration of an attribute, activated on insertion to the corresponding table or update of attribute. Tuple-based CHECK defined in the declaration of a table,

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SQL: Constraints, Triggers, Embedded SQL

SQL: Constraints, Triggers, Embedded SQL. Chapters: 5, 6. Overview. Concepts covered in this lecture: Constraints Triggers SQL in application code Embedded SQL Cursors Dynamic SQL Stored procedures. Integrity Constraints (Review).

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SQL: Queries, Constraints, Triggers Chapter 5 – Part 1

SQL: Queries, Constraints, Triggers Chapter 5 – Part 1. Agenda. Introduction Basic SQL Query Union, Intersection and Except Nested Queries Aggregate Operations Null Values Complex Integrity Constraints in SQL Triggers and Active Databases Design Active Database. About the examples.

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SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers. Content based on Chapter 5 Database Management Systems, (Third Edition), by Raghu Ramakrishnan and Johannes Gehrke. McGraw Hill, 2003. Example Instances. We will use these instances of the Sailors and Reserves relations in our examples.

460 views • 36 slides

SQL: Constraints and Triggers

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Constraints and Triggers

Constraints and Triggers. Foreign Keys Local and Global Constraints Triggers. Constraints and Triggers. A constraint is a relationship among data elements enforced by the DBMS. Example : key constraints. Triggers are operations that are executed when a specified condition occurs

481 views • 46 slides

SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers. 198:541 Rutgers University. R1. Example Instances. We will use these instances of the Sailors and Reserves relations in our examples. If the key for the Reserves relation contained only the attributes sid and bid , how would the semantics differ?. S1.

393 views • 35 slides

SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers. Chapter 5. Why SQL?. SQL is a very-high-level language, in which the programmer is able to avoid specifying a lot of data-manipulation details that would be necessary in languages like C++.

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SQL: Constraints, Triggers, Embedded SQL

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SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers. Chapter 5. Overview: Features of SQL. Data definition language: used to create, destroy, and modify tables and views. Data manipulation language: used to pose queries, and to insert, delete, and modify rows .

381 views • 33 slides

SQL: Queries, Constraints, Triggers

526 views • 47 slides

SQL: Constraints and Triggers

SQL: Constraints and Triggers. Chapter 5, 5.7-5.8. Integrity Constraints (Review). An IC describes conditions that every legal instance of a relation must satisfy. Inserts/deletes/updates that violate IC’s are disallowed.

190 views • 17 slides

SQL: Queries, Constraints, Triggers

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Presentation Transcript

Database Systems I SQL Constraints and Triggers

SQL: Queries, Constraints, Triggers

SQL Triggers

SQL: Queries, Constraints, Triggers

Constraints &amp; Triggers

Constraints &amp; Triggers

SQL: Constraints and Triggers

SQL Constraints and Triggers

SQL: Constraints, Triggers, Embedded SQL

SQL: Queries, Constraints, Triggers Chapter 5 – Part 1

SQL: Queries, Constraints, Triggers

SQL: Constraints and Triggers

Constraints and Triggers

SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers

SQL: Constraints, Triggers, Embedded SQL

SQL: Queries, Constraints, Triggers

SQL: Queries, Constraints, Triggers

SQL: Constraints and Triggers

SQL: Queries, Constraints, Triggers

SQL Constraints and Triggers

Constraints & Triggers

Constraints & Triggers