In-depth discussion of the parameter setting method of Oracle calling stored procedures

Oracle database calling stored procedures is a common database operation technology and is often used in practical applications. When using Oracle database to call a stored procedure, parameters need to be set to meet the needs. This article will delve into the parameter setting method of Oracle calling stored procedures.

1. Definition of stored procedures

A stored procedure is a piece of PL/SQL language program code stored in the Oracle database and is used to complete specific database operation tasks. Stored procedures are generally shared by multiple applications, which can improve the efficiency and security of database applications.

2. Parameters of the stored procedure

The parameters of the stored procedure refer to the variables passed to the stored procedure. Parameters can be divided into three types: input parameters, output parameters and input/output parameters.

1. Input parameters

Input parameters are used as input data sources for stored procedures and can be used for calculation and processing of stored procedures. Input parameters can be any legal data type, such as strings, numbers, dates, cursors, etc.

The syntax for defining input parameters in a stored procedure is as follows:

CREATE PROCEDURE procedure_name(
   input_parameter1 datatype,
   input_parameter2 datatype,
   ...
)

Among them, datatype is the data type of the input parameter, and input_parameter1 is the name of the input parameter. Multiple input parameters are separated by commas.

2. Output parameters

The output parameters are the results of the stored procedure processing, and the processing results are returned to the caller through the output parameters. Output parameters can be of any data type, such as strings, numbers, dates, cursors, etc.

The syntax for defining output parameters in a stored procedure is as follows:

CREATE PROCEDURE procedure_name(
   output_parameter1 OUT datatype,
   output_parameter2 OUT datatype,
   ...
)

Among them, the OUT keyword indicates that the parameter is an output parameter. datatype is the data type of the output parameter, and output_parameter1 is the name of the output parameter. Multiple output parameters are separated by commas.

3. Input/output parameters

Input/output parameters are used to transfer data and return processing results. The syntax for defining input/output parameters in a stored procedure is as follows:

CREATE PROCEDURE procedure_name(
   in_out_parameter1 IN OUT datatype,
   in_out_parameter2 IN OUT datatype,
   ...
)

Among them, the IN keyword indicates that the parameter is an input parameter, and the OUT keyword indicates that the parameter is an output parameter. datatype is the data type of the input/output parameter, in_out_parameter1 is the name of the input/output parameter. Multiple input/output parameters are separated by commas.

3. Calling stored procedures

When using Oracle database to call stored procedures, you need to set parameters for the stored procedures. The following is the syntax for Oracle to call a stored procedure:

EXECUTE procedure_name(input_parameter1, input_parameter2, ..., output_parameter1, output_parameter2, ...)

Among them, EXECUTE is the keyword to execute the stored procedure, procedure_name is the name of the stored procedure, input_parameter1, input_parameter2, etc. are input parameters, and output_parameter1, output_parameter2, etc. are output parameters.

It should be noted that when calling a stored procedure, the parameters must be passed in sequence according to the parameter order defined by the stored procedure, and the output parameters need to be after the input parameters, otherwise the call will fail.

4. Example

The following is a simple Oracle stored procedure example, used to sort the data in a table from small to large by price and output:

CREATE OR REPLACE PROCEDURE sort_table(
   input_table_name IN VARCHAR2,
   output_cursor OUT SYS_REFCURSOR
)
IS
BEGIN
   OPEN output_cursor FOR
      SELECT * FROM input_table_name ORDER BY price ASC;
END;

In When calling this stored procedure, you need to pass the table name and output cursor:

VAR my_cursor REFCURSOR
EXECUTE sort_table('my_table', :my_cursor)
PRINT my_cursor

The above statement will sort the data in the my_table table from small to large by price, store it in a cursor named my_cursor, and output all sorting the subsequent data.

5. Summary

Oracle needs to set parameters when calling a stored procedure, which can be achieved through input parameters, output parameters and input/output parameters. When calling a stored procedure, parameters need to be passed in order according to the parameter order defined by the stored procedure. This article provides a detailed introduction to the parameter setting method of Oracle calling stored procedures. I hope it will be helpful to readers.

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