Module: PostgresHelper

Defined in:
lib/db/postgres.rb

Class Method Summary collapse

Class Method Details

.connect_to_postgres(config) ⇒ Object 



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# File 'lib/db/postgres.rb', line 8

def connect_to_postgres(config)
  conn = PG.connect(
    host: config[:host],
    port: config[:port],
    dbname: config[:database],
    user: config[:username],
    password: config[:password],
    sslmode: config[:sslmode] || 'prefer',
    gssencmode: 'disable',  # Disable GSSAPI encryption
    krbsrvname: nil,        # Disable Kerberos service name
    target_session_attrs: 'read-write'
  )
  conn
end

.disconnect_from_postgres(client) ⇒ Object 



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# File 'lib/db/postgres.rb', line 23

def disconnect_from_postgres(client)
  client.close if client.respond_to?(:close)
end

.format_postgres_config(connection_string) ⇒ Object 



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# File 'lib/db/postgres.rb', line 157

def format_postgres_config(connection_string)
  parsed = URI.parse(connection_string)
  
  {
    host: parsed.host,
    port: parsed.port || 5432,
    database: parsed.path[1..-1],
    username: parsed.user || 'postgres',
    password: parsed.password || '',
    sslmode: parsed.query&.split('&')&.find { |param| param.start_with?('sslmode=') }&.split('=')&.last || 'prefer'
  }
end

.get_columns_by_table_postgres(client, schema_name, table_name) ⇒ Object 



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# File 'lib/db/postgres.rb', line 76

def get_columns_by_table_postgres(client, schema_name, table_name)
  sql = "    SELECT column_name \n    FROM information_schema.columns \n    WHERE table_schema = '\#{schema_name}' \n    AND table_name = '\#{table_name}'\n    ORDER BY ordinal_position\n  SQL\n  \n  results = run_query_postgres(sql, client)\n  results[:rows].map { |row| row['column_name'] }\nend\n"

.get_foreign_keys_postgres(client, schema_name, table_name, primary_key) ⇒ Object 



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# File 'lib/db/postgres.rb', line 89

def get_foreign_keys_postgres(client, schema_name, table_name, primary_key)
  depluralized_table_name = table_name.singularize
  
  sql = "    SELECT column_name \n    FROM information_schema.columns \n    WHERE table_schema = '\#{schema_name}' \n    AND table_name != '\#{table_name}' \n    AND (column_name = '\#{primary_key}' \n      OR column_name = '\#{depluralized_table_name}_\#{primary_key}' \n      OR column_name = '\#{depluralized_table_name}\#{primary_key.capitalize}')\n  SQL\n\n  results = run_query_postgres(sql, client)\n  foreign_keys = results[:rows].map { |key| key['column_name'] }\n  \n  foreign_keys = foreign_keys.reject { |key| ['id', '_id_'].include?(key) }\n  foreign_keys = foreign_keys.uniq\n\n  if foreign_keys.empty?\n    sql = <<~SQL\n      SELECT column_name \n      FROM information_schema.columns \n      WHERE table_schema = '\#{schema_name}' \n      AND table_name != '\#{table_name}' \n      AND (column_name LIKE '\#{table_name}%' \n        OR column_name LIKE '%\\\\_id' \n        OR column_name LIKE '%Id' \n        OR column_name LIKE '%\\\\_\#{primary_key}' \n        OR column_name LIKE '%\#{primary_key.capitalize}')\n    SQL\n\n    results = run_query_postgres(sql, client)\n    foreign_keys = results[:rows].map { |key| key['column_name'] }.uniq\n  end\n\n  foreign_keys\nend\n"

.get_schema_column_info_postgres(client, schema_name, table_names) ⇒ Object 



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# File 'lib/db/postgres.rb', line 128

def get_schema_column_info_postgres(client, schema_name, table_names)
  table_names.map do |table_name|
    query = "      SELECT \n        column_name,\n        udt_name as field_type,\n        ordinal_position as sort_number\n      FROM information_schema.columns\n      WHERE table_schema = '\#{table_name[:schemaName]}'\n      AND table_name = '\#{table_name[:tableName]}'\n      ORDER BY sort_number\n    SQL\n\n    results = run_query_postgres(query, client)\n    {\n      tableName: \"\#{table_name[:schemaName]}.\#{table_name[:tableName]}\",\n      displayName: \"\#{table_name[:schemaName]}.\#{table_name[:tableName]}\",\n      columns: results[:rows].map do |row|\n        {\n          columnName: row['column_name'],\n          displayName: row['column_name'],\n          dataTypeID: get_pg_type_oid(row['field_type']),\n          fieldType: row['field_type']\n        }\n      end\n    }\n  end\nend\n"

.get_schemas_postgres(client) ⇒ Object 



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# File 'lib/db/postgres.rb', line 43

def get_schemas_postgres(client)
  sql = "    SELECT schema_name \n    FROM information_schema.schemata \n    WHERE schema_name NOT LIKE 'pg_%' \n    AND schema_name != 'information_schema'\n  SQL\n  \n  results = run_query_postgres(sql, client)\n  results[:rows].map { |row| row['schema_name'] }\nend\n"

.get_tables_by_schema_postgres(client, schema_names) ⇒ Object 



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# File 'lib/db/postgres.rb', line 55

def get_tables_by_schema_postgres(client, schema_names)
  all_tables = schema_names.flat_map do |schema|
    sql = "      SELECT table_name, table_schema \n      FROM information_schema.tables \n      WHERE table_schema = '\#{schema}'\n      AND table_type = 'BASE TABLE'\n    SQL\n    \n    results = run_query_postgres(sql, client)\n    results[:rows].map do |row|\n      {\n        tableName: row['table_name'],\n        schemaName: row['table_schema']\n      }\n    end\n  end\n\n  all_tables\nend\n"

.run_query_postgres(sql, client) ⇒ Object 



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# File 'lib/db/postgres.rb', line 27

def run_query_postgres(sql, client)
  result = client.exec(sql)
  
  fields = result.fields.map do |field|
    {
      name: field,
      dataTypeID: result.ftype(result.fields.index(field))
    }
  end

  {
    fields: fields,
    rows: result.values.map { |row| result.fields.zip(row).to_h }
  }
end