LOREM 是什么意思？

Question

begin;

create schema if not exists sandbox;

create table sandbox.category
 (
   id    serial primary key,
   name  text not null
 );

insert into sandbox.category(name)
     values ('sport'),('news'),('box office'),('music');

create table sandbox.article
 (
   id         bigserial primary key,
   category   integer references sandbox.category(id),
   title      text not null,
   content    text
 );

create table sandbox.comment
 (
   id         bigserial primary key,
   article    integer references sandbox.article(id),
   content    text
 );

 --SELECT floor(random() * 10 + 1)::int;

insert into sandbox.article(category, title, content)
     select floor(random()*1+3) as category,
            initcap(sandbox.lorem(5)) as title,
            sandbox.lorem(100) as content
       from generate_series(1, 1000) as t(x);

insert into sandbox.comment(article, content)
     select random(1, 1000) as article,
            sandbox.lorem(150) as content
       from generate_series(1, 50000) as t(x);
            
select article.id, category.name, title
  from      sandbox.article
       join sandbox.category
         on category.id = article.category
 limit 3;

select count(*),
       avg(length(title))::int as avg_title_length,
       avg(length(content))::int as avg_content_length
  from sandbox.article;

   select article.id, article.title, count(*)
     from      sandbox.article
          join sandbox.comment
            on article.id = comment.article
group by article.id
order by count desc
   limit 5;

select category.name,
       count(distinct article.id) as articles,
       count(*) as comments
  from      sandbox.category
       left join sandbox.article on article.category = category.id
       left join sandbox.comment on comment.article = article.id
group by category.name
order by category.name;

rollback;

i execute the following code in PSQL:

\ir 'C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql'

The following is the result:

BEGIN
CREATE SCHEMA
CREATE TABLE
INSERT 0 4
CREATE TABLE
CREATE TABLE
psql:C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql:35: ERROR:  function sandbox.lorem(integer) does not exist
LINE 3:             initcap(sandbox.lorem(5)) as title,
                            ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
psql:C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql:40: ERROR:  current transaction is aborted, commands ignored until end of transaction block
psql:C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql:46: ERROR:  current transaction is aborted, commands ignored until end of transaction block
psql:C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql:51: ERROR:  current transaction is aborted, commands ignored until end of transaction block
psql:C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql:59: ERROR:  current transaction is aborted, commands ignored until end of transaction block
psql:C:/Users/Think/Desktop/New folder/TAOP/sql/06-data-modeling/28-repl/01_03_schema_copy.sql:68: ERROR:  current transaction is aborted, commands ignored until end of transaction block
ROLLBACK

I already googled, seems don't have much result. So I really don't know what's LOREM mean? because seems I stuck in line about LOREM. This book name is The Art of PostgreSQL, been following through, so encounter some problem. lorem1 lorem2

Answer 1

Lorem ipsum is a term from the publishing industry. The name refers to fake text filling space on page layout mock-ups. The text at a glance appears to be words from a Latin-based language such as English. But the words are actually all nonsense, gibberish.

Your textbook is using a library to generate such fake text to fill up space in the database fields. This is useful for designing, testing, and demoing systems where live real data is not available. Real data may not yet exist. Or real data may be sensitive/private and therefore inappropriate/illegal to use outside a production system.

Libraries of code are added to Postgres as extensions . Your textbook is apparently calling one such extension. That particular extension is not currently bundled with commonly-used distributions of Postgres. So you will need to obtain such an extension and install it into your Postgres cluster.

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By the way, I happened to ask a similar Question , but for the H2 database rather than Postgres. Being Java-based, an entirely different solution was possible.