diff --git a/pages/总复习2023t1.md b/pages/总复习2023t1.md index 2ccefbf..d849760 100644 --- a/pages/总复习2023t1.md +++ b/pages/总复习2023t1.md @@ -1007,6 +1007,7 @@ - The instances of a potential subclass participate in a relationship unique to that subclass. - DONE Designing databases - Understand Database Design Methodology #flashcard + id:: 6489a99e-3ed0-4673-814d-f823e4998168 - Conceptual database design - The process of constructing a model of the data used in an enterprise, independent of all physical considerations. - Logical database design @@ -1014,6 +1015,7 @@ - Physical database design - The process of producing a description of the implementation of the database (tailored to specific DBMS); - general steps for Database Design Methodology. #flashcard + id:: 6489a9b5-14ea-4b2b-bd47-07b93ae94124 - Gather requirements - Conceptual database design - Logical database design @@ -1021,6 +1023,7 @@ - DONE SQL - purpose and importance of SQL. - SQL is a transform-oriented language with 2 + id:: 6489c210-8ab6-4a38-979a-01af7618a3a4 collapsed:: true major components: #flashcard - A DDL for defining database structure. @@ -1142,6 +1145,7 @@ - Fifth Normal Form (5NF): 5NF is the highest level of normalization and involves decomposing a table into smaller tables to _remove data redundancy and improve data integrity._ - Anomaly - Update Anomalies #flashcard + id:: 6489a420-c0cb-4360-b34f-26a3a01ff46a - Insertion anomalies - If there is a new row inserted in the table and it creates the inconsistency in the table then it is called the insertion anomaly. For @@ -1191,6 +1195,7 @@ - Transaction Transparency: Ensures that all distributed transactions maintain distributed database’s integrity and consistency. - Performance Transparency: must perform as if it were a centralized DBMS. - DONE advantages and disadvantages of distributed databases #flashcard + id:: 6489c210-385e-483b-aa5c-dbe688c5f43b - Advantages - Reflects organizational structure - Improved shareability and local autonomy @@ -1286,6 +1291,7 @@ 3. Partition Tolerance → A query must have an answer, even if the system is partitioned (unless there is a global failure). - BASE: #flashcard + id:: 6489dbd1-f9aa-47fa-8e9f-dfb2c73eff3c - **Basically Available:** Instead of making it compulsory for immediate consistency, BASE-modelled NoSQL databases will ensure the availability of data by