Java DB

Apache Derby

Derby Tools and Utilities Guide

Derby Getting Started
Derby Reference Manual
Derby Developer's Guide
Derby Performance Tuning
Derby Server and Admin Guide
Derby Tools and Utilities
Derby Tools and Utilities
-Copyright
-License
-About this guide
-What are the Derby tools and utilities?
-Using ij
-ij properties reference
-ij commands and errors reference
-ij commands
-Absolute command
-After Last command
-Async command
-Autocommit command
-Before First command
-Close command
-Commit command
-Connect command
-Describe command
-Disconnect command
-Driver command
-Elapsedtime command
-Execute command
-Exit command
-First command
-Get Cursor command
-Get Scroll Insensitive Cursor command
-Help command
-Last command
-LocalizedDisplay command
-MaximumDisplayWidth command
-Next command
-Prepare command
-Previous command
-Protocol command
-Readonly command
-Relative command
-Remove command
-Rollback command
-Run command
-Set Connection command
-Show command
-Wait For command
-Syntax for comments in ij commands
-Syntax for identifiers in ij commands
-Syntax for strings in ij commands
-ij errors
-Using the bulk import and export procedures
-Storing jar files in a database
-sysinfo
-dblook
-SignatureChecker
-Trademarks

 

Syntax for comments in ij commands

Syntax

-- Text

/* Text */

Description

You can use a double dash to create a comment anywhere within an ij command line and as permitted by the underlying connection within SQL commands. The comment is ended at the first new line encountered in the text.

Comments are ignored on input and have no effect on the output displayed.

You can also enclose text in /* */ characters to create either one-line or multi-line comments. Nested comments are permitted. For example, you could put lines like the following into a script named comment.sql:

/* start the file with a /* nested comment */ and see what happens */
connect 'jdbc:derby:newdb;create=true';
values 'hi!';
create table t (x int);
/* use a multi-line comment */
/*
insert into t values 1, 2, 3;
insert into t values 4, 5, 6;
*/
/* end the file with a comment */
values 'This is a test';
/* This is also a test */

Examples

ij> -- this is a comment;
-- the semicolons in the comment are not taken as the end
-- of the command; for that, we put it outside the --:
;
ij> 
ij> run 'comment.sql';
ij> /* start the file with a /* nested comment */ and see what happens */
connect 'jdbc:derby:newdb;create=true';
ij> values 'hi!';
1  
---
hi!

1 row selected
ij> create table t (x int);
0 rows inserted/updated/deleted
ij> /* use a multi-line comment */
/*
insert into t values 1, 2, 3;
insert into t values 4, 5, 6;
*/
/* end the file with a comment */
values 'This is a test';
1             
--------------
This is a test

1 row selected
ij> /* This is also a test */
;
ij> 
 

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