Computer Science XII

SQL Data Types

ata types in SQL defines a sort of value that a database table column can contain. In a database table, each column is required to have a data type with a name.

What Are Data Types in SQL?

Every value controlled by Oracle Database has a specific data type. The data type of value links a fixed set of properties with the desired value. These properties treat values of one data type differently from values of another. Let us take an example, where you can add values of NUMBER data type, but not values of a RAW data type. When you create a table or a cluster, you must have to state a data type for each of its columns. When you create a procedure or stored function, you need to state a data type for each of its arguments. These data types classify the domain of values that each column can hold, or each argument can comprise.

Oracle Database provides many built-in data types as well as several categories for user-defined types that can be used as data types. A data type is either scalar or non-scalar. A scalar type holds an atomic value, whereas a non-scalar, which is also called a "collection," contains a set of values. A large object (LOB) is an unusual form of scalar data type which represents a considerable scalar value of binary or character data.

Types of Data Types

User-Defined Types: User-defined data types employ Oracle's built-in data types and few other user-defined data types as the construction blocks for object types, which models the configuration and actions of data in applications.

  • CHAR (character)
  • DEC (Decimal)
  • INT (Integer)
  • REAL

Oracle-Supplied Types: Oracle offers SQL-based interfaces for defining new types when the built-in or ANSI-supported types are not satisfactory. The performance and working for these types can be implemented in C/C++, Java, or PL/ SQL. Oracle Database repeatedly allows the low-level infrastructure services needed for input-output, varied client-side access for new data types, and optimizations for data transferring between the application and the database. The Oracle-supplied types, along with cross-references to the documentation of their implementation listed as following:

  • Any Types
  • XML Types
  • Spatial Types
  • Media Types
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