MongoDB wasn’t designed in a lab. We built MongoDB from our own experiences building large scale, high availability, robust
systems. We didn’t start from scratch, we really tried to figure out what was broken, and tackle that. So the way I think about
MongoDB is that if you take MySql, and change the data model from relational to document based, you get a lot of great
features: embedded docs for speed, manageability, agile development with schema-less databases, easier horizontal scalability
because joins aren’t as important. There are lots of things that work great in relational databases: indexes, dynamic queries and
updates to name a few, and we haven’t changed much there. For example, the way you design your indexes in MongoDB
should be exactly the way you do it in MySql or Oracle, you just have the option of indexing an embedded field.
MongoDB wasn’t designed in a lab. We built MongoDB from our own experiences building large scale, high availability, robust
systems. We didn’t start from scratch, we really tried to figure out what was broken, and tackle that. So the way I think about
MongoDB is that if you take MySql, and change the data model from relational to document based, you get a lot of great
features: embedded docs for speed, manageability, agile development with schema-less databases, easier horizontal scalability
because joins aren’t as important. There are lots of things that work great in relational databases: indexes, dynamic queries and
updates to name a few, and we haven’t changed much there. For example, the way you design your indexes in MongoDB
should be exactly the way you do it in MySql or Oracle, you just have the option of indexing an embedded field.
PL/SQL, Oracle's procedural extension of SQL, is an advanced fourth-generation
programming language (4GL). It offers software-engineering features such as data
encapsulation, overloading, collection types, exceptions, and information hiding.
PL/SQL also supports rapid prototyping and development through tight integration
with SQL and the Oracle database.
Anyone developing PL/SQL-based applications for Oracle should read this book. This
book is intended for programmers, systems analysts, project managers, database
administrators, and others who need to automate database operations. People
developing applications in other languages can also produce mixed-language
applications with parts written in PL/SQL.
To use this guide effectively, you need a working knowledge of the Oracle database,
the SQL language, and basic programming constructs such as IF-THEN comparisons,
loops, procedures, and functions.
ORACLE内部结构编写Oracle Database Concepts is intended for database administrators, system
administrators, and database application developers.
To use this document, you need to know the following:
Relational database concepts in general
Concepts and terminology in Chapter 1, "Introduction to the Oracle Database"
The operating system environment under which you are running Oracle