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Ryan 2023-06-14 15:15:30 +08:00
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pages/总复习2023t1.md
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@ -1007,6 +1007,7 @@
- The instances of a potential subclass participate in a relationship unique to that subclass.
- DONE Block 3
- DONE DB transaction management
- anomalies
- DONE ACID (Atomicity, Consistency, Isolation, Durability): A set of properties that guarantee the reliability and integrity of database transactions.
- Atomicity: The property that ensures a transaction is treated as a single, indivisible unit of work. It either executes all its operations successfully or rolls back to the initial state if any operation fails.
- Consistency: The property that ensures a transaction transforms the database from one consistent state to another consistent state. It maintains data integrity and adheres to defined business rules.
@ -1033,7 +1034,7 @@
validation checks, concurrency control mechanisms can ensure that
transactions are executed in a way that maintains data consistency and
serializability.
- DONE Recovery Control
- ==DONE Recovery Control==
- DONE Some causes of database failure.
- System crashes, resulting in loss of main memory.
- Power failures
@ -1103,14 +1104,13 @@
- Performance Transparency: must perform as if it were a centralized DBMS.
- advantages and disadvantages of distributed databases
- DONE XML
collapsed:: true
- XML definition and basic concepts
- LATER XML definition and basic concepts
collapsed:: true
- eXtensible Markup Language
- A meta-language (i.e. a language for describing other languages) that
enables designers to create their own customised tags to provide
functionality not available with HTML.
- Relational model versus XML
- LATER Relational model versus XML
collapsed:: true
- SQL
collapsed:: true
@ -1121,12 +1121,12 @@
- is a markup specification language
- You can: design ways of describing information (text or data), usually for storage, transmission, or processing by a program (you can use it in combination with a programming language).
- It says nothing about what you should do with the data (although your choice of element names may hint at what they are for).
- Well-formed XML, Valid XML
- LATER Well-formed XML, Valid XML
collapsed:: true
- Adheres to basic structural requirements - Single root element
- Matched tags, proper nesting
- Unique attributes within elements
- DTD, XSD
- LATER DTD, XSD
collapsed:: true
- DTD: Defines the valid syntax of an XML document
- XSD: a more comprehensive method of defining content model of