Basic usage

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## Basic usage

These examples contain user defined functions similar to legacy MySQL functions.

Example #1 PostgreSQL user defined functions example

    <?php// This function should be needed, since PostgreSQL connection binds database.function pg_list_dbs($db){    assert(is_resource($db));    $query = 'SELECT d.datname as "Name", u.usename as "Owner", pg_encoding_to_char(d.encoding) as "Encoding"FROM pg_database d LEFT JOIN pg_user u ON d.datdba = u.usesysidORDER BY 1;';    return pg_query($db, $query);}// List tables.function pg_list_tables($db){    assert(is_resource($db));    $query = "SELECT c.relname as \"Name\", CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'i' THEN 'index' WHEN 'S' THEN 'sequence' WHEN 's' THEN 'special' END as \"Type\",  u.usename as \"Owner\"FROM pg_class c LEFT JOIN pg_user u ON c.relowner = u.usesysidWHERE c.relkind IN ('r','v','S','') AND c.relname !~ '^pg_'ORDER BY 1;";    return pg_query($db, $query);}// See also pg_meta_data(). It returns field definition as array.function pg_list_fields($db, $table){    assert(is_resource($db));    $query = "SELECT a.attname, format_type(a.atttypid, a.atttypmod), a.attnotnull, a.atthasdef, a.attnumFROM pg_class c, pg_attribute aWHERE c.relname = '".$table."' AND a.attnum > 0 AND a.attrelid = c.oidORDER BY a.attnum;";    return pg_query($db, $query);}?>