What does desc mean in oracle

DESC (DESCRIBE) command is used to describe the structure of a table or view in an Oracle database, providing information about columns, data types, size, nullability, and other details. The specific steps are as follows: Use syntax: DESC table_name; Return information: column name, data type, size, nullability, default value, constraints.

#What does desc mean in oracle?

DESC (DESCRIBE) command is used to describe the structure of a table or view in an Oracle database. It provides information about the columns, data types, size, nullability, and other details of a table or view.

Use the syntax

<code class="sql">DESC table_name;</code>

where table_name is the name of the table or view to be described.

Return information

The DESC command returns the following information about the table or view:

• Column name: table column names in .
• Data type: The data type of each column (such as VARCHAR2, NUMBER, DATE).
• Size: The maximum amount of data that can be stored in each column.
• Nullable: Indicates whether the column allows null values ​​(YES or NO).
• Default value: The default value of the column, NULL if not specified.
• Constraints: Any constraints applied to the column (such as NOT NULL, UNIQUE, PRIMARY KEY).

Example

The following example describes the employees table:

<code class="sql">DESC employees;</code>

The output will look like this:

<code>Column Name          Data Type            Length   Nullable  Default     Primary/Foreign Key
--------------------- -------------------- -------- -------- ---------- ---------------
employee_id          NUMBER               22        NO
first_name           VARCHAR2             25        YES         NULL              
last_name            VARCHAR2             25        YES         NULL              
email                VARCHAR2             255       NO         NULL              
phone_number         VARCHAR2             20        YES         NULL              
hire_date            DATE                 7        NO         NULL              
job_id               VARCHAR2             10        NO         NULL              
salary               NUMBER               22        YES         NULL              
manager_id           NUMBER               22        YES         NULL              
department_id        NUMBER               22        YES         NULL              </code>

This output shows the detailed structure of the columns in the employees table, including data type, size, nullability, default value, and any constraints.

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