Class: Pcrd::Schema::ObjectReader

Inherits:
Object
  • Object
show all
Defined in:
lib/pcrd/schema/object_reader.rb

Overview

Reads the “secondary” schema objects that the load DDL deliberately omits (Schema::DDL creates only the table + primary key). Used by the target-readiness manifest to report and regenerate what must exist on the target before cutover.

Works against either cluster — point it at the source to discover objects, at the target to see what already exists.

Defined Under Namespace

Classes: Constraint, Grant, IdentityColumn, Index

Instance Method Summary collapse

Constructor Details

#initialize(pool) ⇒ ObjectReader

Returns a new instance of ObjectReader.



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# File 'lib/pcrd/schema/object_reader.rb', line 18

def initialize(pool)
  @pool = pool
end

Instance Method Details

#column_comments(table_name, schema_name: "public") ⇒ Object

Hash<column_name, comment> for columns that have a COMMENT.



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# File 'lib/pcrd/schema/object_reader.rb', line 85

def column_comments(table_name, schema_name: "public")
  @pool.exec(COLUMN_COMMENTS_SQL, [table_name, schema_name])
       .each_with_object({}) { |r, h| h[r["attname"]] = r["comment"] }
end

#constraints(table_name, schema_name: "public") ⇒ Object

Foreign-key, unique, and check constraints (not the primary key).



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# File 'lib/pcrd/schema/object_reader.rb', line 36

def constraints(table_name, schema_name: "public")
  @pool.exec(CONSTRAINTS_SQL, [table_name, schema_name]).map do |r|
    Constraint.new(
      name:       r["conname"],
      kind:       r["contype"],
      definition: r["definition"],
      columns:    split_list(r["columns"])
    )
  end
end

#grants(table_name, schema_name: "public") ⇒ Object

Explicit table privileges (the owner’s implicit grant is excluded), one Grant per grantee with its sorted privilege list.



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# File 'lib/pcrd/schema/object_reader.rb', line 65

def grants(table_name, schema_name: "public")
  owner_name = owner(table_name, schema_name: schema_name)
  by_grantee = Hash.new { |h, k| h[k] = [] }

  @pool.exec(GRANTS_SQL, [table_name, schema_name]).each do |r|
    next if r["grantee"] == owner_name # owner already has everything

    by_grantee[r["grantee"]] << r["privilege_type"]
  end

  by_grantee.map { |grantee, privs| Grant.new(grantee: grantee, privileges: privs.sort) }
end

#identity_columns(table_name, schema_name: "public") ⇒ Object

Identity (GENERATED … AS IDENTITY) and serial (nextval default) columns.



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# File 'lib/pcrd/schema/object_reader.rb', line 48

def identity_columns(table_name, schema_name: "public")
  @pool.exec(IDENTITY_SQL, [table_name, schema_name]).map do |r|
    IdentityColumn.new(
      column: r["attname"],
      kind:   r["attidentity"].to_s.empty? ? "serial" : "identity"
    )
  end
end

#indexes(table_name, schema_name: "public") ⇒ Object

Non-PK indexes that are not backing a unique/PK constraint (those are reported under #constraints instead, to avoid double-counting).



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# File 'lib/pcrd/schema/object_reader.rb', line 24

def indexes(table_name, schema_name: "public")
  @pool.exec(INDEXES_SQL, [table_name, schema_name]).map do |r|
    Index.new(
      name:       r["index_name"],
      definition: r["definition"],
      unique:     r["indisunique"] == "t",
      columns:    split_list(r["columns"])
    )
  end
end

#owner(table_name, schema_name: "public") ⇒ Object

The table’s owner role name.



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# File 'lib/pcrd/schema/object_reader.rb', line 58

def owner(table_name, schema_name: "public")
  row = @pool.exec(OWNER_SQL, [table_name, schema_name])
  row.ntuples.zero? ? nil : row[0]["owner"]
end

#table_comment(table_name, schema_name: "public") ⇒ Object

The table’s COMMENT, or nil.



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# File 'lib/pcrd/schema/object_reader.rb', line 79

def table_comment(table_name, schema_name: "public")
  row = @pool.exec(TABLE_COMMENT_SQL, [table_name, schema_name])
  row.ntuples.zero? ? nil : row[0]["comment"]
end