model merging

boilingcore/imports.go

@@ -179,11 +179,16 @@ func newImporter() importer {
 	}
 
 	imp.Singleton = mapImports{
-		"boil_queries": {
+		"boil_queries": imports{
+			standard: importList{
+				`"database/sql"`,
+				`"strings"`,
+			},
 			thirdParty: importList{
 				`"github.com/lbryio/sqlboiler/boil"`,
 				`"github.com/lbryio/sqlboiler/queries"`,
 				`"github.com/lbryio/sqlboiler/queries/qm"`,
+				`"github.com/pkg/errors"`,
 			},
 		},
 		"boil_types": {

templates/23_merge.tpl

@@ -0,0 +1,84 @@
+{{- $tableNamePlural := .Table.Name | plural | titleCase -}}
+{{- $tableNameSingular := .Table.Name | singular | titleCase -}}
+{{- if .Table.IsJoinTable -}}
+{{- else -}}
+	{{- $dot := . }}
+// Merge combines two {{$tableNamePlural}} into one. The primary record will be kept, and the secondary will be deleted.
+func Merge{{$tableNamePlural}}(exec boil.Executor, primaryID uint64, secondaryID uint64) error {
+	txdb, ok := exec.(boil.Beginner)
+	if !ok {
+		return errors.New("database does not support transactions")
+	}
+
+	tx, txErr := txdb.Begin()
+	if txErr != nil {
+		return txErr
+	}
+
+  primary, err := Find{{$tableNameSingular}}(tx, primaryID)
+  if err != nil {
+    tx.Rollback()
+    return err
+  }
+	if primary == nil {
+		return errors.New("Primary {{$tableNameSingular}} not found")
+	}
+
+  secondary, err := Find{{$tableNameSingular}}(tx, secondaryID)
+  if err != nil {
+    tx.Rollback()
+    return err
+  }
+	if secondary == nil {
+		return errors.New("Secondary {{$tableNameSingular}} not found")
+	}
+
+  relatedFields := map[string]string{
+	{{- range .Tables -}}
+	  {{- range .FKeys -}}
+	    {{- if eq $dot.Table.Name .ForeignTable }}
+		  "{{.Table }}": "{{ .Column}}",
+      {{- end -}}
+    {{- end -}}
+  {{- end }}
+  }
+  err = mergeModels(tx, primaryID, secondaryID, relatedFields)
+  if err != nil {
+    tx.Rollback()
+    return err
+  }
+
+	pr := reflect.ValueOf(primary)
+	sr := reflect.ValueOf(secondary)
+	// for any column thats null on the primary and not null on the secondary, copy from secondary to primary
+	for i := 0; i < sr.Elem().NumField(); i++ {
+		pf := pr.Elem().Field(i)
+		sf := sr.Elem().Field(i)
+		if sf.IsValid() {
+			if nullable, ok := sf.Interface().(Nullable); ok && !nullable.IsZero() && pf.Interface().(Nullable).IsZero() {
+				pf.Set(sf)
+			}
+		}
+	}
+
+	err = primary.Update(tx)
+	if err != nil {
+		tx.Rollback()
+		return errors.WithStack(err)
+	}
+
+	err = secondary.Delete(tx)
+	if err != nil {
+		tx.Rollback()
+		return errors.WithStack(err)
+	}
+
+  tx.Commit()
+  return nil
+}
+
+// Merge combines two {{$tableNamePlural}} into one. The primary record will be kept, and the secondary will be deleted.
+func Merge{{$tableNamePlural}}G(primaryID uint64, secondaryID uint64) error {
+  return Merge{{$tableNamePlural}}(boil.GetDB(), primaryID, secondaryID)
+}
+{{- end -}}{{/* join table */}}

templates/singleton/boil_queries.tpl

@@ -19,3 +19,57 @@ func NewQuery(exec boil.Executor, mods ...qm.QueryMod) *queries.Query {
 
 	return q
 }
+
+func mergeModels(tx *sql.Tx, primaryID uint64, secondaryID uint64, relatedFields map[string]string) error {
+	if len(relatedFields) < 1 {
+    return nil
+  }
+
+  for table, column := range relatedFields {
+    // TODO: use NewQuery here, not plain sql
+    query := "UPDATE " + table + " SET " + column + " = ? WHERE " + column + " = ?"
+    _, err := tx.Exec(query, primaryID, secondaryID)
+    if err != nil {
+      return errors.WithStack(err)
+    }
+  }
+  return checkMerge(tx, relatedFields)
+}
+
+func checkMerge(tx *sql.Tx, fields map[string]string) error {
+	columns := []interface{}{}
+	seenColumns := map[string]bool{}
+	placeholders := []string{}
+	for _, column := range fields {
+		if _, ok := seenColumns[column]; !ok {
+			columns = append(columns, column)
+			seenColumns[column] = true
+			placeholders = append(placeholders, "?")
+
+		}
+	}
+
+	placeholder := strings.Join(placeholders, ", ")
+
+	q := `SELECT table_name, column_name FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA=DATABASE() AND column_name IN (` + placeholder + `)`
+	rows, err := tx.Query(q, columns...)
+	defer rows.Close()
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	for rows.Next() {
+		var tableName string
+		var columnName string
+		err = rows.Scan(&tableName, &columnName)
+		if err != nil {
+			return errors.WithStack(err)
+		}
+
+		if _, exists := fields[tableName]; !exists {
+			return errors.New("Missing merge for " + tableName + "." + columnName)
+		}
+	}
+
+	return nil
+}