使用PHP检查PostgreSQL中是否存在数据库

Question

I was wondering if anyone would be able to tell me about whether it is possible to use PHP to check if a postgresql database exists?

I am writing a PHP script and I only want it to create the database if it doesn't already exist but up to now haven't been able to see how to implement it.

Thank you

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I've tried

$cmd = 'psql -U postgres -c "SELECT schema_name FROM information_schema.schemata WHERE schema_name = 'portal';"';
    exec($cmd);

I got

PHP Parse error:  syntax error, unexpected 'portal'

Answer 1

You have a syntax error singe the single quote is used to initalize the statement.

$cmd = 'psql -U postgres -c "SELECT schema_name FROM information_schema.schemata WHERE schema_name = \'portal\';"';
exec($cmd);

You should use PDO instead of exec, but this would probably work for you.

Answer 2

You are confusing schema and database . in postgres it is schema what you call database in mysql. so if you want to find a database, better use pg_databases

$cmd = 'psql -U postgres -c "select \'already_there\' from pg_database where datname = \'db1\';"';
    exec($cmd);

Answer 3

这是PHP错误，您必须转义'\\'portal \\''