Delimiters
Delimiters are symbols used by Oracle for a special purpose.In other words a delimiter is a simple or compound symbol that has a special meaning to PL/SQL. They act as separators,
database link indicators, mathematical operators, and concatenation operators.
The following table lists the delimiters available.
| Delimiter | Description |
| +, –, *, /, ** | Mathematical operators |
| .. | Range operator, frequently used in for-loops |
| <, >, <>, =, !=, ~=, ^=, <=, >= |
Relational operators (greater than, less than, etc.) |
| –, /*, */ | Comment indicators (single line and multiline) |
| <<, >> | Label delimiters |
| % | Attribute indicator, used with TYPE, ROWTYPE, NOTFOUND, and other attributes |
| (, ) | Expression delimiters, often used in the WHERE clause with AND and OR operators |
| : | Bind variable indicator—bind variables are used for performance reasons in PL/SQL to reduce the number of parses required for SQL where only the values of the variables change and not the structure of the SQL itself |
| , | Item separator—a comma separates lists whenever present in PL/SQL |
| ‘ | Character string delimiter—strings or character literals between two single quotes are case sensitive |
| “ | Quoted identifier delimiter—quoted identifiers are case sensitive and can contain spaces and special characters |
| @ | Database link delimiter—in a SQL statement the string following this symbol is the database name that is linked to the current instance |
| ; | Statement terminator, used at the completion of every statement or declaration in PL/SQL to signify the completion of the command |
| := | Assignment delimiter—this delimiter initializes variables (to the left of the operator) with values (to the right of the operator) |
| => | Association operator, used when calling a procedure or function, passing values to the parameters |
| || | Concatenation operator, combines the string on the left with the string on the right of the operator |