bases de dados relacionais
Definição à espera.
Definição à espera.
graph LR
Center["bases de dados relacionais"]:::main
Pre_data_structures["data-structures"]:::pre --> Center
click Pre_data_structures "/terms/data-structures"
Pre_logic["logic"]:::pre --> Center
click Pre_logic "/terms/logic"
Center --> Child_sql["sql"]:::child
click Child_sql "/terms/sql"
Center --> Child_postgresql["postgresql"]:::child
click Child_postgresql "/terms/postgresql"
Rel_nosql["nosql"]:::related -.-> Center
click Rel_nosql "/terms/nosql"
Rel_data_warehouse["data-warehouse"]:::related -.-> Center
click Rel_data_warehouse "/terms/data-warehouse"
Rel_relational_database["relational-database"]:::related -.-> Center
click Rel_relational_database "/terms/relational-database"
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🧒 Explique como se eu tivesse 5 anos
Think of a library's card catalog. Each card (row) has information about a book (like title, author), and the cards are organized in a way that lets you easily find all books by a specific author or all books on a certain topic (relationships).
🤓 Expert Deep Dive
The relational model, introduced by E.F. Codd, provides a theoretical foundation based on set theory and first-order predicate logic. Data is represented in normalized tables to reduce redundancy and improve data integrity. Normalization forms (1NF, 2NF, 3NF, BCNF) guide the design process. Relational [database](/pt/terms/relational-database) management systems (RDBMS) implement SQL as the standard language for data definition, manipulation, and control. Query optimization is a critical component, where the RDBMS's query optimizer determines the most efficient execution plan for SQL queries, often involving techniques like indexing (B-trees, hash indexes), join algorithms (nested loop, hash join, merge join), and query rewriting. Transaction management ensures ACID properties through mechanisms like locking, logging (write-ahead logging), and concurrency control protocols (e.g., two-phase locking). Distributed relational databases introduce complexities in maintaining consistency and availability across multiple nodes, often employing techniques like two-phase commit (2PC).