How to Declare Variables in Oracle SQL Scripts?

Declaring variables in Oracle SQL scripts

When writing reusable SQL scripts, you may need to declare variables and use them throughout the script. Variables can be declared using different methods, each with its own advantages and limitations.

Use VAR to declare bind variables

Bind variables are used to interact with stored procedures or functions that have OUT parameters. To declare a VAR variable, use the following syntax:

<code class="language-sql">SQL> var variable_name data_type;</code>

Use EXEC to assign values ​​to variables:

<code class="language-sql">SQL> exec :variable_name := 'value';</code>

Use substitution variables

Replacement variables are available in interactive mode. They allow you to enter values ​​at runtime:

<code class="language-sql">SQL> accept variable_name prompt "Enter value: ";</code>

Use &variable_name to access variables.

Use DEFINE to initialize script variables

DEFINE variables are used to initialize variables before running the script:

<code class="language-sql">SQL> def variable_name value;</code>

Use anonymous PL/SQL blocks

Anonymous PL/SQL blocks provide a structured way to declare and use variables:

<code class="language-sql">SQL> declare
2    variable_name data_type;
3    cursor_statement;
4  begin
5    script_logic;
6  end;
7  /</code>

The method you choose to declare variables depends on the specific requirements of your script. However, be sure to avoid variable name conflicts and ensure that variables are declared in the correct scope.

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