dbstore

Documentation

Overview

Package dbstore stores and retrieves Go data structures as rows in a SQL database.

Each struct type is stored in its own table, and each field is a separate column of that table. This package makes it easy to store structs into such a database and to read them back out.

Index

• Variables
• type Context
• type Storage
  • func (db *Storage) CreateTables(ctxt Context) error
  • func (db *Storage) Delete(ctxt Context, val interface{}) error
  • func (db *Storage) Insert(ctxt Context, val interface{}) error
  • func (db *Storage) Read(ctxt Context, val interface{}, columns ...string) error
  • func (db *Storage) Register(val interface{})
  • func (db *Storage) Select(ctxt Context, val interface{}, query string, args ...interface{}) error
  • func (db *Storage) Write(ctxt Context, val interface{}, columns ...string) error

Variables

var Debug = false

If Debug is set to true, each Storage method will print a log of the SQL commands being executed.

var ErrNotFound = errors.New("database record not found")

ErrNotFound is the error returned by Read, Select, and Write when there are no matching records in the database.

Types

type Context

type Context interface {
	Exec(query string, args ...interface{}) (sql.Result, error)
	Query(query string, args ...interface{}) (*sql.Rows, error)
}

A Context represents the underlying SQL database. Typically a *sql.DB is used as the Context implementation, but the interface allows debugging adapters to be substituted.

type Storage

type Storage struct {
	// contains filtered or unexported fields
}

A Storage records information about the data structures being stored. It must be initialized by one or more calls to Register before the other methods are called.

func (*Storage) CreateTables

func (db *Storage) CreateTables(ctxt Context) error

CreateTables creates the tables to hold the registered types. It only needs to be called when creating a new database. Each table is named for the type it stores, in the form "full/import/path.TypeName".

func (*Storage) Delete

func (db *Storage) Delete(ctxt Context, val interface{}) error

Delete deletes the value from the database. The unique identification fields in val must be set.

Delete executes a command like:

delete from Structs
where Key1 = val.Key1 and Key2 = val.Key2

func (*Storage) Insert

func (db *Storage) Insert(ctxt Context, val interface{}) error

Insert inserts the value into the database.

func (*Storage) Read

func (db *Storage) Read(ctxt Context, val interface{}, columns ...string) error

Read reads the named columns from the database into val. The key fields in val must already be set.

Read executes a command like:

select columns from Structs
where Key1 = val.Key1 AND Key2 = val.Key2

func (*Storage) Register

func (db *Storage) Register(val interface{})

Register records that the storage should store values with the type of val, which should be a pointer to a struct with exported fields.

func (*Storage) Select

func (db *Storage) Select(ctxt Context, val interface{}, query string, args ...interface{}) error

Select executes a select command to read one or more rows into val. To read values of type Example, val may take any of these types:

*Example - read a single Example, returning ErrNotFound if not found
**Example - allocate and read a single Example, setting it to nil if not found
*[]Example - read a slice of Examples
*[]*Example - read a slice of Examples

Select executes a command like

select Key1, Key2, Field3, Field4 from Structs
<query here>

func (*Storage) Write

func (db *Storage) Write(ctxt Context, val interface{}, columns ...string) error

Write writes the named columns from val into the database. The key fields in val must already be set and the value must already exist.

Write executes a command like:

update Structs
set column1 = val.Column1, column2 = val.Column2
where Key1 = val.Key1 AND Key2 = val.Key2