Masterminds/squirrel: Difference between revisions
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=Internal= | =Internal= | ||
* [[PostgreSQL_Support_in_Go#Overview|PostgreSQL Support in Go]] | * [[PostgreSQL_Support_in_Go#Overview|PostgreSQL Support in Go]] | ||
=TODO= | |||
<font color=darkkhaki> | |||
* PARSE: https://github.com/Masterminds/squirrel | |||
* PARSE: https://medium.com/nerd-for-tech/postgres-libraries-to-try-with-go-8f80191edbff | |||
</font> | |||
=Overview= | =Overview= | ||
< | Squirrel is a fluent SQL generator for Go. It helps build SQL queries from composable parts representing the SQL SELECT query clauses: <code>[[SQL_SELECT#SELECT|SELECT]]</code>, <code>[[SQL_SELECT#FROM|FROM]]</code>, <code>[[SQL_Querying_Multiple_Tables#Join|JOIN]]</code>, <code>[[SQL_WHERE#Overview|WHERE]]</code>, etc. and also other DML statements. | ||
=Installation= | =Installation= | ||
<syntaxhighlight lang='go'> | |||
go get github.com/Masterminds/squirrel | |||
</syntaxhighlight> | |||
=Programming Model= | |||
==Queries== | |||
<syntaxhighlight lang='go'> | |||
import sq "github.com/Masterminds/squirrel" | |||
// Get a database/sql database handle | |||
dbHandle = getDbHandle() | |||
// Build the query with a fluent API | |||
query = sq.Select("*").From("person") | |||
// execute the query with the database handle; the syntax is identical to that used with dbHandle.Query() | |||
rows, err := query.RunWith(dbHandle).Query() | |||
if err != nil { ... } | |||
defer func() { | |||
if err = rows.Close(); err != nil { ... } | |||
}() | |||
for rows.Next() { | |||
var ( | |||
id int | |||
name string | |||
city sql.NullString | |||
) | |||
if err = rows.Scan(&id, &name, &city); err != nil { ... } | |||
fmt.Printf("id: %d, name: %s, city: %s\n", id, name, city.String) | |||
} | |||
</syntaxhighlight> | |||
<code>getDbHandle()</code> can be implemented as shown in: {{Internal|PostgreSQL_Support_in_Go#With_database/sql_API_and_a_pgx_Driver|Connect to a PostgreSQL Database with <tt>database/sql</tt> API and a pgx Driver}} | |||
==Parameterized Statements== | |||
The format of the [[SQL#Parameterized_SQL_Statements|parameterized statements]] depends on the database. For example, in PostgreSQL, the placeholders are introduced by <code>$</code> and have numerical values, etc. | |||
===PostgreSQL Parameterized Statements=== | |||
The parameterized statement placeholders in Squirrel are <code>?</code>. To configure it to generate correct PostgreSQL parameterized statements, we must configure the specific [[PostgreSQL_Concepts#Placeholder_Format|PostgreSQL placeholder format]], which is <code>$<number></code>. | |||
<syntaxhighlight lang='go'> | |||
import sq "github.com/Masterminds/squirrel" | |||
query := | |||
sq.Select("*"). | |||
From("person"). | |||
Where("name IN (?, ?)", "Alice", "Bob"). | |||
PlaceholderFormat(sq.Dollar) | |||
</syntaxhighlight> | |||
Also see: {{Internal|PostgreSQL_Concepts#Parameterized_SQL_Statements|Parameterized PostgreSQL SQL Statements}} |
Latest revision as of 18:32, 31 May 2024
External
- https://github.com/Masterminds/squirrel
- https://medium.com/nerd-for-tech/postgres-libraries-to-try-with-go-8f80191edbff
Internal
TODO
- PARSE: https://github.com/Masterminds/squirrel
- PARSE: https://medium.com/nerd-for-tech/postgres-libraries-to-try-with-go-8f80191edbff
Overview
Squirrel is a fluent SQL generator for Go. It helps build SQL queries from composable parts representing the SQL SELECT query clauses: SELECT
, FROM
, JOIN
, WHERE
, etc. and also other DML statements.
Installation
go get github.com/Masterminds/squirrel
Programming Model
Queries
import sq "github.com/Masterminds/squirrel"
// Get a database/sql database handle
dbHandle = getDbHandle()
// Build the query with a fluent API
query = sq.Select("*").From("person")
// execute the query with the database handle; the syntax is identical to that used with dbHandle.Query()
rows, err := query.RunWith(dbHandle).Query()
if err != nil { ... }
defer func() {
if err = rows.Close(); err != nil { ... }
}()
for rows.Next() {
var (
id int
name string
city sql.NullString
)
if err = rows.Scan(&id, &name, &city); err != nil { ... }
fmt.Printf("id: %d, name: %s, city: %s\n", id, name, city.String)
}
getDbHandle()
can be implemented as shown in:
Parameterized Statements
The format of the parameterized statements depends on the database. For example, in PostgreSQL, the placeholders are introduced by $
and have numerical values, etc.
PostgreSQL Parameterized Statements
The parameterized statement placeholders in Squirrel are ?
. To configure it to generate correct PostgreSQL parameterized statements, we must configure the specific PostgreSQL placeholder format, which is $<number>
.
import sq "github.com/Masterminds/squirrel"
query :=
sq.Select("*").
From("person").
Where("name IN (?, ?)", "Alice", "Bob").
PlaceholderFormat(sq.Dollar)
Also see: