Merge pull request #800 from chenghonour/master

Add database method

database/gdb/gdb.go

@@ -142,6 +142,7 @@ type DB interface {
 	QuotePrefixTableName(table string) string
 	Tables(schema ...string) (tables []string, err error)
 	TableFields(table string, schema ...string) (map[string]*TableField, error)
+	HasTable(name string) (bool, error)
 
 	// HandleSqlBeforeCommit is a hook function, which deals with the sql string before
 	// it's committed to underlying driver. The parameter <link> specifies the current

database/gdb/gdb_core.go

@@ -778,3 +778,17 @@ func (c *Core) writeSqlToLogger(v *Sql) {
 		c.logger.Debug(s)
 	}
 }
+
+// HasTable determine whether the table name exists in the database.
+func (c *Core) HasTable(name string) (bool, error) {
+	tableList, err := c.DB.Tables()
+	if err != nil {
+		return false, err
+	}
+	for _, table := range tableList {
+		if table == name {
+			return true, nil
+		}
+	}
+	return false, nil
+}

database/gdb/gdb_model_fields.go

@@ -127,3 +127,24 @@ func (m *Model) FieldsExStr(fields string, prefix ...string) string {
 	newFields = m.db.QuoteString(newFields)
 	return newFields
 }
+
+// HasField determine whether the field exists in the table.
+func (m *Model) HasField(field string) (bool, error) {
+	tableFields, err := m.db.TableFields(m.tables)
+	if err != nil {
+		return false, err
+	}
+	if len(tableFields) == 0 {
+		return false, fmt.Errorf(`empty table fields for table "%s"`, m.tables)
+	}
+	fieldsArray := make([]string, len(tableFields))
+	for k, v := range tableFields {
+		fieldsArray[v.Index] = k
+	}
+	for _, f := range fieldsArray {
+		if f == field {
+			return true, nil
+		}
+	}
+	return false, nil
+}

database/gdb/gdb_z_mysql_model_test.go

@@ -2437,3 +2437,37 @@ func Test_Model_Empty_Slice_Argument(t *testing.T) {
 		t.Assert(len(result), 0)
 	})
 }
+
+func Test_Model_HasTable(t *testing.T) {
+	table := createTable()
+	defer dropTable(table)
+
+	gtest.C(t, func(t *gtest.T) {
+		result, err := db.HasTable(table)
+		t.Assert(result, true)
+		t.Assert(err, nil)
+	})
+
+	gtest.C(t, func(t *gtest.T) {
+		result, err := db.HasTable("table12321")
+		t.Assert(result, false)
+		t.Assert(err, nil)
+	})
+}
+
+func Test_Model_HasField(t *testing.T) {
+	table := createTable()
+	defer dropTable(table)
+
+	gtest.C(t, func(t *gtest.T) {
+		result, err := db.Table(table).HasField("id")
+		t.Assert(result, true)
+		t.Assert(err, nil)
+	})
+
+	gtest.C(t, func(t *gtest.T) {
+		result, err := db.Table(table).HasField("id123")
+		t.Assert(result, false)
+		t.Assert(err, nil)
+	})
+}