/
reader.go
219 lines (210 loc) · 5 KB
/
reader.go
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package clickhouse
import (
"database/sql"
"strings"
"github.com/xo/usql/drivers"
"github.com/xo/usql/drivers/metadata"
)
type MetadataReader struct {
metadata.LoggingReader
}
// NewMetadataReader creates the metadata reader for clickhouse databases.
func NewMetadataReader(db drivers.DB, opts ...metadata.ReaderOption) metadata.Reader {
return &MetadataReader{
LoggingReader: metadata.NewLoggingReader(db, opts...),
}
}
func (r MetadataReader) Tables(f metadata.Filter) (*metadata.TableSet, error) {
qstr := `SELECT
database AS Schema,
name AS Name,
COALESCE(
IF(database LIKE 'system', 'SYSTEM TABLE', null),
IF(is_temporary,'LOCAL TEMPORARY', null),
IF(engine LIKE 'View', 'VIEW', null),
'TABLE'
) AS Type,
COALESCE(total_bytes, 0) AS Size,
comment as Comment
FROM
system.tables`
var conds []string
var vals []interface{}
if !f.WithSystem {
conds = append(conds, "database NOT LIKE 'system'")
}
if f.Schema != "" {
vals = append(vals, f.Schema)
conds = append(conds, "database LIKE ?")
}
if f.Name != "" {
vals = append(vals, f.Name)
conds = append(conds, "name LIKE ?")
}
if len(f.Types) != 0 {
var pholders []string
for _, t := range f.Types {
vals = append(vals, t)
pholders = append(pholders, "?")
}
if len(pholders) != 0 {
conds = append(conds, "Type IN ("+strings.Join(pholders, ", ")+")")
}
}
rows, closeRows, err := r.query(qstr, conds, "Schema, Name", vals...)
if err != nil {
return nil, err
}
defer closeRows()
var results []metadata.Table
for rows.Next() {
var rec metadata.Table
if err := rows.Scan(&rec.Schema, &rec.Name, &rec.Type, &rec.Size, &rec.Comment); err != nil {
return nil, err
}
results = append(results, rec)
}
if rows.Err() != nil {
return nil, rows.Err()
}
return metadata.NewTableSet(results), nil
}
func (r MetadataReader) Columns(f metadata.Filter) (*metadata.ColumnSet, error) {
qstr := `SELECT
position,
database as schema,
name,
type,
COALESCE(default_expression, '')
FROM
system.columns`
vals := []interface{}{f.Parent}
conds := []string{"table LIKE ?"}
if f.Schema != "" {
vals = append(vals, f.Schema)
conds = append(conds, "database LIKE ?")
}
if f.Name != "" {
vals = append(vals, f.Name)
conds = append(conds, "name LIKE ?")
}
if len(f.Types) != 0 {
var pholders []string
for _, t := range f.Types {
vals = append(vals, t)
pholders = append(pholders, "?")
}
if len(pholders) != 0 {
conds = append(conds, "Type IN ("+strings.Join(pholders, ", ")+")")
}
}
rows, closeRows, err := r.query(qstr, conds, "name", vals...)
if err != nil {
return nil, err
}
defer closeRows()
var results []metadata.Column
for rows.Next() {
rec := metadata.Column{
Catalog: f.Catalog,
Table: f.Parent,
}
if err := rows.Scan(
&rec.OrdinalPosition,
&rec.Schema,
&rec.Name,
&rec.DataType,
&rec.Default,
); err != nil {
return nil, err
}
results = append(results, rec)
}
if rows.Err() != nil {
return nil, rows.Err()
}
return metadata.NewColumnSet(results), nil
}
func (r MetadataReader) Schemas(f metadata.Filter) (*metadata.SchemaSet, error) {
qstr := `SELECT
name
FROM
system.databases`
var conds []string
var vals []interface{}
if f.Name != "" {
vals = append(vals, f.Name)
conds = append(conds, "name LIKE ?")
}
rows, closeRows, err := r.query(qstr, conds, "name", vals...)
if err != nil {
return nil, err
}
defer closeRows()
var results []metadata.Schema
for rows.Next() {
var rec metadata.Schema
if err := rows.Scan(&rec.Schema); err != nil {
return nil, err
}
results = append(results, rec)
}
if rows.Err() != nil {
return nil, rows.Err()
}
return metadata.NewSchemaSet(results), nil
}
func (r MetadataReader) Functions(f metadata.Filter) (*metadata.FunctionSet, error) {
qstr := `SELECT
name AS specific_name,
name AS routine_name,
(IF(is_aggregate = 1,'AGGREGATE','FUNCTION')) AS type
FROM
system.functions`
var conds []string
var vals []interface{}
if f.Name != "" {
conds = append(conds, "name LIKE ?")
vals = append(vals, f.Name)
}
if len(f.Types) != 0 {
var pholders []string
for _, t := range f.Types {
vals = append(vals, t)
pholders = append(pholders, "?")
}
if len(pholders) != 0 {
conds = append(conds, "type IN ("+strings.Join(pholders, ", ")+")")
}
}
rows, closeRows, err := r.query(qstr, conds, "name, type", vals...)
if err != nil {
return nil, err
}
defer closeRows()
var results []metadata.Function
for rows.Next() {
var rec metadata.Function
if err := rows.Scan(
&rec.SpecificName,
&rec.Name,
&rec.Type,
); err != nil {
return nil, err
}
results = append(results, rec)
}
if rows.Err() != nil {
return nil, rows.Err()
}
return metadata.NewFunctionSet(results), nil
}
func (r MetadataReader) query(qstr string, conds []string, order string, vals ...interface{}) (*sql.Rows, func(), error) {
if len(conds) != 0 {
qstr += "\nWHERE " + strings.Join(conds, " AND ")
}
if order != "" {
qstr += "\nORDER BY " + order
}
return r.Query(qstr, vals...)
}