How can I use Oracle SQL to communicate?

Structured Query Language StructuredQuery Language (SQL) is the main query Language today. It is mainly used to manage mainstream DBMS-relational DBMSRDBMS ). All Database-related communication will be done through DBMS. To do this, you can use SQL or other similar things. Database System Administrator DBA) uses the query language to establish and maintain the database. You can use the query language to access the database and view or change the data. The following describes the Oracle SQL language:

Recently, the Object-Oriented, OO) DBMS has become the most prominent database management system and has found many suitable application environments, such as CAD/CAM, engineering, multimedia, etc. Object-oriented DBMS is suitable for applications in these fields because it has the ability to control complex data types in an almost non-transactional environment. Due to competition, RDBMS vendors have created commercially available Universal Servers to provide object-oriented/multimedia performance that includes text, audio, images, and video data. Oracle's UniversalServer is an example. In addition, the user-defined data type or extensible type has been extended or added to the core database server, so Oracle8 provides such performance. RDBMS products like this are considered to be mixed, but they are much more intrusive than previous RDBMS products.

In addition, the Multi-dimensional database Multi-DimensionalDatabase, MDD) shares some market share. These databases contain many variables that must be accessed or listed by multiple dimensions, such as behavior science data) applications provide highly indexed data. In traditional RDBMS, this is almost impossible. Databases can only be used independently. Furthermore, to compete with MDD, RDBMS vendors provide their own hierarchical products that provide super-indexed data and use special technologies such as bit ing indexes. Oracle Express is an example of a multi-dimensional database.
You have learned about the main tasks of DBMS. To learn more about what an RDBMS is composed of, you must first understand the relational model. The following situations occur in a relational model:
■ The basic item of data is the relationship.
■ Operations on these tables only generate relational close ).

What is a link? This is a mathematical concept that describes how two sets of elements interact with each other or how they correspond one by one. Therefore, the relational model is based on mathematics.

However, for you, a link is just a table with some special attributes. A relational model organizes data into a table and is only in the table. Customers, database designers, database system administrators, and users view data in the same way-from a table. A table is a synonym of a relational model. A relational table has a group of named attribute) or columns, and a group of tuple) or rows. Sometimes a column is called a field and a row is called a record. The intersection of a column and a row is usually called a unit. Position of a column, with a scope or data type, such as a character or integer. A relational table must meet certain conditions to become part of the relational model.

■ Data stored in a unit must be atomic. Each unit can store only one piece of data, which is also called the Information Principle InformationPrinciple ). Although many systems have been built in the past few years in some ways that violate this line, this violation will not apply to good design principles. When a unit contains more than one information, this is called Information encoding ionioncoding), a good example is a Vehicle identification number Vehicle IdentificationNumber, VIN ). If it is stored as a column, it violates the information principle because it contains multiple pieces of information, such as origin, model, factory, and so on. In this case, whether or not to adopt a solution that violates the theory is a design choice problem, although in most cases, the results prove that this is a disadvantage for data integrity.

■ The data stored in the column must have the same data type.

■ Each row is unique and does not have exactly the same rows ).

■ No column order.

■ Rows have no order.

■ The column has a unique name.

In addition to tables and their attributes, the relational model has its own special operations.

Prior to the dominant Oracle SQL language, a competitive language was the QUEL or QUEry language from Ingres, and a Unified UDL Data Language, the Unified DataLanguage ). ANSI) is a broad range of standard entities, including computer software languages such as SQL) standards.

Oracle SQL is not only a Data Definition Language (DDL), but also a data operation language (DML ). Database System Administrators and Users can access the database in the same language. The last thing that a relational model requires is two basic integrity principles. They are entity integrity principles entity integrityrule) and reference integrity principles referentialintegrityrule ). First, let's look at two definitions:
■ Primary key primarykey) is a set of columns or columns that uniquely identify a row. Sometimes, multiple or multiple columns can be treated as primary keys.
■ A primary key consisting of multiple columns is called the connection key concatenatedkey) and the compoundkey), or compositekey ).

The Database Designer determines which columns can be combined to reflect the business situation most accurately and effectively. This does not mean that other data is not stored, but that group of columns is selected as the primary key. One

RDBMS is a DBMS that is built on the above Relational Models and generally meets all the mentioned requirements.

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