Documentation
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Overview ¶
Package formatsql implements SQL export formatting for query results. It generates INSERT, INSERT OR IGNORE, and INSERT OR UPDATE statements that can be used for database migration, backup/restore, and test data generation.
This package registers its formatters with the format package's registry, allowing it to be used as a plugin without the format package depending on memefish.
Current Design Constraints: - Values are expected to be pre-formatted as SQL literals using spanvalue.LiteralFormatConfig - The formatter receives []Cell (Row) but uses RawText() to extract plain string values - Format decision is made early in execute_sql.go, not at formatting time
The implementation uses memefish's ast.Path for correct identifier handling.
Index ¶
Constants ¶
const ( ModeSQLInsert format.Mode = "SQL_INSERT" ModeSQLInsertOrIgnore format.Mode = "SQL_INSERT_OR_IGNORE" ModeSQLInsertOrUpdate format.Mode = "SQL_INSERT_OR_UPDATE" )
SQL export mode constants matching enums.DisplayMode string values.
Variables ¶
This section is empty.
Functions ¶
func ExtractTableNameFromQuery ¶
ExtractTableNameFromQuery attempts to extract a table name from a simple SELECT query. It supports simple SELECT patterns including:
- SELECT * FROM table_name
- SELECT columns FROM table_name
- SELECT * FROM table_name WHERE ...
- SELECT * FROM table_name ORDER BY ...
- SELECT * FROM table_name LIMIT ...
- SELECT DISTINCT columns FROM table_name (DISTINCT is allowed since Spanner tables always have PKs)
- Combinations of the above
NOT supported:
- GROUP BY / HAVING (aggregations change the result set structure)
- JOINs (combine multiple tables)
- Subqueries, CTEs, UNIONs (complex structures)
Note: DISTINCT is allowed because Spanner tables always have primary keys, making SELECT * results inherently unique. DISTINCT on unique results is a no-op.
Returns:
- (tableName, nil) when extraction succeeds
- ("", error) when extraction fails with a reason
The error messages are intended for debug logging to help understand why auto-detection failed, allowing users to adjust their queries or use explicit CLI_SQL_TABLE_NAME setting.
func FormatSQL ¶
func FormatSQL(mode format.Mode) format.FormatFunc
FormatSQL is the non-streaming formatter for SQL export.
func ParseSimpleTablePath ¶
ParseSimpleTablePath converts a simple table path string from CLI input to an ast.Path. This function handles user-friendly input where reserved words don't need quoting. Examples: "Users", "Order" (reserved word OK), "myschema.Users" The function does NOT parse SQL expressions - it simply splits on dots. Quoting for reserved words is handled automatically by ast.Ident.SQL() during output.
Types ¶
type SQLFormatter ¶
type SQLFormatter struct {
// contains filtered or unexported fields
}
SQLFormatter handles SQL export formatting for different INSERT variants. It supports both single-row and multi-row INSERT statements based on batchSize. The formatter buffers rows when batchSize > 1 to generate multi-row INSERTs.
func NewSQLFormatter ¶
func NewSQLFormatter(out io.Writer, mode format.Mode, tableName string, batchSize int64) (*SQLFormatter, error)
NewSQLFormatter creates a new SQL formatter for streaming output.
func (*SQLFormatter) Finish ¶
func (f *SQLFormatter) Finish() error
Finish flushes any remaining rows.
func (*SQLFormatter) WriteHeader ¶
func (f *SQLFormatter) WriteHeader(columnNames []string) error
WriteHeader sets up column names for the formatter.
func (*SQLFormatter) WriteRow ¶
func (f *SQLFormatter) WriteRow(values []string) error
WriteRow processes a single row and outputs SQL when batch is full.
type SQLStreamingFormatter ¶
type SQLStreamingFormatter struct {
// contains filtered or unexported fields
}
SQLStreamingFormatter implements StreamingFormatter for SQL export.
func NewSQLStreamingFormatter ¶
func NewSQLStreamingFormatter(out io.Writer, config format.FormatConfig, mode format.Mode) (*SQLStreamingFormatter, error)
NewSQLStreamingFormatter creates a new streaming SQL formatter.
func (*SQLStreamingFormatter) FinishFormat ¶
func (s *SQLStreamingFormatter) FinishFormat() error
FinishFormat completes the SQL export.
func (*SQLStreamingFormatter) InitFormat ¶
func (s *SQLStreamingFormatter) InitFormat(columnNames []string, config format.FormatConfig, previewRows []format.Row) error
InitFormat initializes the formatter with column information.
Source Files