add comments for orm packages, part 2

@@ -927,6 +927,7 @@ func (d *dbBase) GenerateOperatorSql(mi *modelInfo, fi *fieldInfo, operator stri
 	return sql, params
 }
 
+// gernerate sql string with inner function, such as UPPER(text).
 func (d *dbBase) GenerateOperatorLeftCol(*fieldInfo, string, *string) {
 	// default not use
 }

@@ -4,6 +4,7 @@ import (
 	"fmt"
 )
 
+// mysql operators.
 var mysqlOperators = map[string]string{
 	"exact":     "= ?",
 	"iexact":    "LIKE ?",
@@ -21,6 +22,7 @@ var mysqlOperators = map[string]string{
 	"iendswith":   "LIKE ?",
 }
 
+// mysql column field types.
 var mysqlTypes = map[string]string{
 	"auto":            "AUTO_INCREMENT NOT NULL PRIMARY KEY",
 	"pk":              "NOT NULL PRIMARY KEY",
@@ -41,29 +43,35 @@ var mysqlTypes = map[string]string{
 	"float64-decimal": "numeric(%d, %d)",
 }
 
+// mysql dbBaser implementation.
 type dbBaseMysql struct {
 	dbBase
 }
 
 var _ dbBaser = new(dbBaseMysql)
 
+// get mysql operator.
 func (d *dbBaseMysql) OperatorSql(operator string) string {
 	return mysqlOperators[operator]
 }
 
+// get mysql table field types.
 func (d *dbBaseMysql) DbTypes() map[string]string {
 	return mysqlTypes
 }
 
+// show table sql for mysql.
 func (d *dbBaseMysql) ShowTablesQuery() string {
 	return "SELECT table_name FROM information_schema.tables WHERE table_type = 'BASE TABLE' AND table_schema = DATABASE()"
 }
 
+// show columns sql of table for mysql.
 func (d *dbBaseMysql) ShowColumnsQuery(table string) string {
 	return fmt.Sprintf("SELECT COLUMN_NAME, COLUMN_TYPE, IS_NULLABLE FROM information_schema.columns "+
 		"WHERE table_schema = DATABASE() AND table_name = '%s'", table)
 }
 
+// execute sql to check index exist.
 func (d *dbBaseMysql) IndexExists(db dbQuerier, table string, name string) bool {
 	row := db.QueryRow("SELECT count(*) FROM information_schema.statistics "+
 		"WHERE table_schema = DATABASE() AND table_name = ? AND index_name = ?", table, name)
@@ -72,6 +80,7 @@ func (d *dbBaseMysql) IndexExists(db dbQuerier, table string, name string) bool
 	return cnt > 0
 }
 
+// create new mysql dbBaser.
 func newdbBaseMysql() dbBaser {
 	b := new(dbBaseMysql)
 	b.ins = b

 package orm
 
+// oracle dbBaser
 type dbBaseOracle struct {
 	dbBase
 }
 
 var _ dbBaser = new(dbBaseOracle)
 
+// create oracle dbBaser.
 func newdbBaseOracle() dbBaser {
 	b := new(dbBaseOracle)
 	b.ins = b

@@ -5,6 +5,7 @@ import (
 	"strconv"
 )
 
+// postgresql operators.
 var postgresOperators = map[string]string{
 	"exact":       "= ?",
 	"iexact":      "= UPPER(?)",
@@ -20,6 +21,7 @@ var postgresOperators = map[string]string{
 	"iendswith":   "LIKE UPPER(?)",
 }
 
+// postgresql column field types.
 var postgresTypes = map[string]string{
 	"auto":            "serial NOT NULL PRIMARY KEY",
 	"pk":              "NOT NULL PRIMARY KEY",
@@ -40,16 +42,19 @@ var postgresTypes = map[string]string{
 	"float64-decimal": "numeric(%d, %d)",
 }
 
+// postgresql dbBaser.
 type dbBasePostgres struct {
 	dbBase
 }
 
 var _ dbBaser = new(dbBasePostgres)
 
+// get postgresql operator.
 func (d *dbBasePostgres) OperatorSql(operator string) string {
 	return postgresOperators[operator]
 }
 
+// generate functioned sql string, such as contains(text).
 func (d *dbBasePostgres) GenerateOperatorLeftCol(fi *fieldInfo, operator string, leftCol *string) {
 	switch operator {
 	case "contains", "startswith", "endswith":
@@ -59,6 +64,7 @@ func (d *dbBasePostgres) GenerateOperatorLeftCol(fi *fieldInfo, operator string,
 	}
 }
 
+// postgresql unsupports updating joined record.
 func (d *dbBasePostgres) SupportUpdateJoin() bool {
 	return false
 }
@@ -67,10 +73,13 @@ func (d *dbBasePostgres) MaxLimit() uint64 {
 	return 0
 }
 
+// postgresql quote is ".
 func (d *dbBasePostgres) TableQuote() string {
 	return `"`
 }
 
+// postgresql value placeholder is $n.
+// replace default ? to $n.
 func (d *dbBasePostgres) ReplaceMarks(query *string) {
 	q := *query
 	num := 0
@@ -97,6 +106,7 @@ func (d *dbBasePostgres) ReplaceMarks(query *string) {
 	*query = string(data)
 }
 
+// make returning sql support for postgresql.
 func (d *dbBasePostgres) HasReturningID(mi *modelInfo, query *string) (has bool) {
 	if mi.fields.pk.auto {
 		if query != nil {
@@ -107,18 +117,22 @@ func (d *dbBasePostgres) HasReturningID(mi *modelInfo, query *string) (has bool)
 	return
 }
 
+// show table sql for postgresql.
 func (d *dbBasePostgres) ShowTablesQuery() string {
 	return "SELECT table_name FROM information_schema.tables WHERE table_type = 'BASE TABLE' AND table_schema NOT IN ('pg_catalog', 'information_schema')"
 }
 
+// show table columns sql for postgresql.
 func (d *dbBasePostgres) ShowColumnsQuery(table string) string {
 	return fmt.Sprintf("SELECT column_name, data_type, is_nullable FROM information_schema.columns where table_schema NOT IN ('pg_catalog', 'information_schema') and table_name = '%s'", table)
 }
 
+// get column types of postgresql.
 func (d *dbBasePostgres) DbTypes() map[string]string {
 	return postgresTypes
 }
 
+// check index exist in postgresql.
 func (d *dbBasePostgres) IndexExists(db dbQuerier, table string, name string) bool {
 	query := fmt.Sprintf("SELECT COUNT(*) FROM pg_indexes WHERE tablename = '%s' AND indexname = '%s'", table, name)
 	row := db.QueryRow(query)
@@ -127,6 +141,7 @@ func (d *dbBasePostgres) IndexExists(db dbQuerier, table string, name string) bo
 	return cnt > 0
 }
 
+// create new postgresql dbBaser.
 func newdbBasePostgres() dbBaser {
 	b := new(dbBasePostgres)
 	b.ins = b

@@ -5,6 +5,7 @@ import (
 	"fmt"
 )
 
+// sqlite operators.
 var sqliteOperators = map[string]string{
 	"exact":       "= ?",
 	"iexact":      "LIKE ? ESCAPE '\\'",
@@ -20,6 +21,7 @@ var sqliteOperators = map[string]string{
 	"iendswith":   "LIKE ? ESCAPE '\\'",
 }
 
+// sqlite column types.
 var sqliteTypes = map[string]string{
 	"auto":            "integer NOT NULL PRIMARY KEY AUTOINCREMENT",
 	"pk":              "NOT NULL PRIMARY KEY",
@@ -40,38 +42,47 @@ var sqliteTypes = map[string]string{
 	"float64-decimal": "decimal",
 }
 
+// sqlite dbBaser.
 type dbBaseSqlite struct {
 	dbBase
 }
 
 var _ dbBaser = new(dbBaseSqlite)
 
+// get sqlite operator.
 func (d *dbBaseSqlite) OperatorSql(operator string) string {
 	return sqliteOperators[operator]
 }
 
+// generate functioned sql for sqlite.
+// only support DATE(text).
 func (d *dbBaseSqlite) GenerateOperatorLeftCol(fi *fieldInfo, operator string, leftCol *string) {
 	if fi.fieldType == TypeDateField {
 		*leftCol = fmt.Sprintf("DATE(%s)", *leftCol)
 	}
 }
 
+// unable updating joined record in sqlite.
 func (d *dbBaseSqlite) SupportUpdateJoin() bool {
 	return false
 }
 
+// max int in sqlite.
 func (d *dbBaseSqlite) MaxLimit() uint64 {
 	return 9223372036854775807
 }
 
+// get column types in sqlite.
 func (d *dbBaseSqlite) DbTypes() map[string]string {
 	return sqliteTypes
 }
 
+// get show tables sql in sqlite.
 func (d *dbBaseSqlite) ShowTablesQuery() string {
 	return "SELECT name FROM sqlite_master WHERE type = 'table'"
 }
 
+// get columns in sqlite.
 func (d *dbBaseSqlite) GetColumns(db dbQuerier, table string) (map[string][3]string, error) {
 	query := d.ins.ShowColumnsQuery(table)
 	rows, err := db.Query(query)
@@ -92,10 +103,12 @@ func (d *dbBaseSqlite) GetColumns(db dbQuerier, table string) (map[string][3]str
 	return columns, nil
 }
 
+// get show columns sql in sqlite.
 func (d *dbBaseSqlite) ShowColumnsQuery(table string) string {
 	return fmt.Sprintf("pragma table_info('%s')", table)
 }
 
+// check index exist in sqlite.
 func (d *dbBaseSqlite) IndexExists(db dbQuerier, table string, name string) bool {
 	query := fmt.Sprintf("PRAGMA index_list('%s')", table)
 	rows, err := db.Query(query)
@@ -113,6 +126,7 @@ func (d *dbBaseSqlite) IndexExists(db dbQuerier, table string, name string) bool
 	return false
 }
 
+// create new sqlite dbBaser.
 func newdbBaseSqlite() dbBaser {
 	b := new(dbBaseSqlite)
 	b.ins = b

@@ -6,6 +6,7 @@ import (
 	"time"
 )
 
+// table info struct.
 type dbTable struct {
 	id    int
 	index string
@@ -18,6 +19,7 @@ type dbTable struct {
 	jtl   *dbTable
 }
 
+// tables collection struct, contains some tables.
 type dbTables struct {
 	tablesM map[string]*dbTable
 	tables  []*dbTable
@@ -26,6 +28,8 @@ type dbTables struct {
 	skipEnd bool
 }
 
+// set table info to collection.
+// if not exist, create new.
 func (t *dbTables) set(names []string, mi *modelInfo, fi *fieldInfo, inner bool) *dbTable {
 	name := strings.Join(names, ExprSep)
 	if j, ok := t.tablesM[name]; ok {
@@ -42,6 +46,7 @@ func (t *dbTables) set(names []string, mi *modelInfo, fi *fieldInfo, inner bool)
 	return t.tablesM[name]
 }
 
+// add table info to collection.
 func (t *dbTables) add(names []string, mi *modelInfo, fi *fieldInfo, inner bool) (*dbTable, bool) {
 	name := strings.Join(names, ExprSep)
 	if _, ok := t.tablesM[name]; ok == false {
@@ -54,11 +59,14 @@ func (t *dbTables) add(names []string, mi *modelInfo, fi *fieldInfo, inner bool)
 	return t.tablesM[name], false
 }
 
+// get table info in collection.
 func (t *dbTables) get(name string) (*dbTable, bool) {
 	j, ok := t.tablesM[name]
 	return j, ok
 }
 
+// get related fields info in recursive depth loop.
+// loop once, depth decreases one.
 func (t *dbTables) loopDepth(depth int, prefix string, fi *fieldInfo, related []string) []string {
 	if depth < 0 || fi.fieldType == RelManyToMany {
 		return related
@@ -79,6 +87,7 @@ func (t *dbTables) loopDepth(depth int, prefix string, fi *fieldInfo, related []
 	return related
 }
 
+// parse related fields.
 func (t *dbTables) parseRelated(rels []string, depth int) {
 
 	relsNum := len(rels)
@@ -140,6 +149,7 @@ func (t *dbTables) parseRelated(rels []string, depth int) {
 	}
 }
 
+// generate join string.
 func (t *dbTables) getJoinSql() (join string) {
 	Q := t.base.TableQuote()
 
@@ -186,6 +196,7 @@ func (t *dbTables) getJoinSql() (join string) {
 	return
 }
 
+// parse orm model struct field tag expression.
 func (t *dbTables) parseExprs(mi *modelInfo, exprs []string) (index, name string, info *fieldInfo, success bool) {
 	var (
 		jtl *dbTable
@@ -300,6 +311,7 @@ loopFor:
 	return
 }
 
+// generate condition sql.
 func (t *dbTables) getCondSql(cond *Condition, sub bool, tz *time.Location) (where string, params []interface{}) {
 	if cond == nil || cond.IsEmpty() {
 		return
@@ -364,6 +376,7 @@ func (t *dbTables) getCondSql(cond *Condition, sub bool, tz *time.Location) (whe
 	return
 }
 
+// generate order sql.
 func (t *dbTables) getOrderSql(orders []string) (orderSql string) {
 	if len(orders) == 0 {
 		return
@@ -392,6 +405,7 @@ func (t *dbTables) getOrderSql(orders []string) (orderSql string) {
 	return
 }
 
+// generate limit sql.
 func (t *dbTables) getLimitSql(mi *modelInfo, offset int64, limit int64) (limits string) {
 	if limit == 0 {
 		limit = int64(DefaultRowsLimit)
@@ -414,6 +428,7 @@ func (t *dbTables) getLimitSql(mi *modelInfo, offset int64, limit int64) (limits
 	return
 }
 
+// crete new tables collection.
 func newDbTables(mi *modelInfo, base dbBaser) *dbTables {
 	tables := &dbTables{}
 	tables.tablesM = make(map[string]*dbTable)

@@ -6,6 +6,7 @@ import (
 	"time"
 )
 
+// get table alias.
 func getDbAlias(name string) *alias {
 	if al, ok := dataBaseCache.get(name); ok {
 		return al
@@ -15,6 +16,7 @@ func getDbAlias(name string) *alias {
 	return nil
 }
 
+// get pk column info.
 func getExistPk(mi *modelInfo, ind reflect.Value) (column string, value interface{}, exist bool) {
 	fi := mi.fields.pk
 
@@ -37,6 +39,7 @@ func getExistPk(mi *modelInfo, ind reflect.Value) (column string, value interfac
 	return
 }
 
+// get fields description as flatted string.
 func getFlatParams(fi *fieldInfo, args []interface{}, tz *time.Location) (params []interface{}) {
 
 outFor: